The vagina: how does it work?

Anatomy of the vagina: what science measures

The vagina is an elastic muscular canal that connects the vaginal introitus—the entrance, located in the vulva—to the cervix. Its wall consists of mucosa, richly vascularized connective tissue, and circular and longitudinal muscle layers. It is a dynamic organ whose dimensions vary with the menstrual cycle, arousal, and age.

Dimensions and variability

Vaginal dimensions vary significantly between individuals and change during arousal:

• Length at rest: An MRI study of 28 participants measured an average length of 62.7 mm (≈ 6.3 cm), with a range of 5 to 13 cm according to a large clinical cohort.
• Length during arousal: Masters & Johnson data indicate an unstimulated length of 7.0 to 8.3 cm and an aroused length of 10.8 to 12.1 cm—an increase of approximately 30 to 50% due to vascular engorgement.
• Width: The vagina is wider near the cervix (≈ 32 mm), narrows at the pelvic diaphragm (≈ 27 mm), and is narrower at the entrance (≈ 26 mm).
• Elasticity: The vagina is highly extensible—it dilates during arousal as well as childbirth. Its size at rest is not correlated with sexual satisfaction.

Innervation and sensitivity

The distribution of nerve endings in the vagina is uneven—and this inequality explains most variations in sensitivity between women and between different areas of the vagina.

• Lower third (near the entrance): This is the most richly innervated area. It contains most of the somatic nerve endings, innervated by the pudendal nerve (S2–S4), responsible for precise tactile sensations.
• Upper two-thirds: Primarily sensitive to pressure through less densely distributed autonomic fibers. These areas perceive pressure and filling more than fine touch.
• Distal anterior wall: A histological study measured a density of 4.34 ± 0.35 fibers/mm² in the lamina propria of the distal third, compared with 2.34 ± 0.29 fibers/mm² in the proximal third—almost twice as many nerve fibers at the entrance as at the far end. Vascular density is also higher there.

This concentration of nerves in the distal third of the anterior wall explains why most women feel sexual sensations mainly in the first few centimeters of the vagina — rather than deeper inside.

The G-spot: real area, anatomical myth?

The term "G-spot" was popularized in the 1980s in reference to urologist Ernst Gräfenberg. It refers to an area of the anterior vaginal wall, a few centimeters from the opening, whose stimulation is said to produce intense orgasms or female ejaculation. Scientific research has since considerably nuanced this definition.

Not a point, but a complex

Imaging and anatomical dissection studies suggest that the area known as the "G-spot" actually corresponds to the convergence of several structures — referred to as the clitourethrovaginal complex (CUV):

• The internal branches of the clitoris (crura and vestibular bulbs)
• The periurethral tissue — the Skene's glands, analogous to the male prostate
• The anterior vaginal wall

This complex is located approximately 3 to 4 cm from the vaginal opening. The orgasm achieved by stimulating this area would largely result from the indirect compression of the internal clitoris when the swollen erectile bodies press against the anterior vaginal wall — rather than from stimulating a distinct organ.

Lack of anatomical consensus

A 2021 systematic review analyzed 31 studies on the subject and concluded that there is no scientific consensus allowing the G-spot to be defined as a distinct anatomical structure. Imaging and histological studies are contradictory — some identify connective or glandular tissue thickening in this area, while others show nothing specific.

What women feel

Despite the lack of unanimous anatomical evidence, self-reports are consistent:

• In a systematic review involving 5,072 participants, 62.9% report having a G-spot or a more sensitive area, 84.3% believe such an area exists, and 65.9% indicate that they have one — 55.1% on the anterior wall and 7.3% on the posterior wall.
• Among women who report having a G-spot, 72.6% report experiencing an orgasm when it is stimulated, and 40% report ejaculating.
• A survey of 309 women (2018) shows that those who believe in the existence of the G-spot have significantly better sexual function and less sexual dysfunction (45.6% versus 67.8% among nonbelievers).

The role of urethrovaginal thickness

An ultrasound study measured the urethrovaginal space (UVS) in non-pregnant women. Result: a thicker space in the distal part (≈ 9.3 ± 2.2 mm) is strongly correlated with the ability to achieve vaginal orgasm (r = 0.884; p = 0.015). Women with a thinner urethrovaginal space have significantly fewer vaginal orgasms. This individual, unmodifiable morphological variation partly explains why some women respond very well to stimulation of the anterior wall while others respond little or not at all.

Vaginal orgasm and clitoral orgasm: what the research says

The classic distinction between "vaginal orgasm" and "clitoral orgasm" is anatomically reductive. Scientific data show that the two are closely linked — and that penetration alone is rarely sufficient.

A study published in the Journal of Sexual Medicine (2023) on heterosexual women:

The conclusion is clear: more than 90% of women who reach orgasm during intercourse need clitoral stimulation — either alone or combined with penetration. Orgasm from penetration alone is the exception, not the norm. When it occurs, it most likely involves indirect stimulation of the CUV complex — the internal branches of the clitoris compressed by penetration — rather than a clitoris-independent vaginal response.

Female ejaculation and squirting

Female ejaculation and squirting are two distinct phenomena, often confused, that are the subject of growing scientific research.

Two different phenomena

• Female ejaculation: release of a thick, whitish fluid produced by the Skene's glands (paraurethral glands located around the urethra). These glands are analogous to the male prostate and secrete PSA (prostate-specific antigen). The volume is small.
• Squirting: expulsion of a clear, abundant fluid originating mainly from the bladder. Its composition is similar to diluted urine. The volume can be substantial. Both phenomena may occur simultaneously.

What the 2024 Swedish study says

A cross-sectional survey conducted in Sweden among 1,568 women is the most comprehensive study available on the subject to date:

Key points to remember: female ejaculation is a common phenomenon (58% of women surveyed), perceived positively by most, but often initially confusing—notably because of the fear of having urinated (26%). It is neither a dysfunction nor a performance goal to achieve: among women who had not experienced it, only one-third wanted it to happen.

Who it is for: understanding individual variations

Sensitivity of the anterior wall

The nerve density of the distal anterior vaginal wall varies between individuals. Some women have a concentration of nerves and urethrovaginal tissue thickness that make this area highly responsive—they respond well to curved sex toys that apply pressure to the first few centimeters of the anterior wall. Others have less sensitivity in this area and respond better to external clitoral stimulation.

Preference for deep vs. distal stimulation

The upper two-thirds of the vagina are primarily sensitive to pressure and fullness, rather than precise touch. Women who enjoy a feeling of “fullness” benefit more from larger-diameter sex toys than from very long sex toys. Length is not the determining factor—width and curvature matter more.

Sensitivity varies according to arousal

The vagina lengthens by 30 to 50% during arousal. A sex toy that seems too long when not aroused may become perfectly suitable once arousal is established. Conversely, stimulating without sufficient prior arousal reduces natural lubrication and tissue receptivity, making penetration uncomfortable regardless of the quality of the sex toy.

After menopause

The decrease in estrogen leads to thinning of the vaginal lining, reduced natural lubrication, and a slight decrease in elasticity. These changes make consistent water-based lubrication, smaller-diameter sex toys initially, and longer preliminary stimulation advisable. They do not mean the end of vaginal pleasure.

How to choose your vaginal sex toy

The curve

The most important criterion for stimulating the anterior wall. An upward curve positioned 3 to 4 cm deep reaches the CUV complex—the most richly innervated area. A straight sex toy applies uniform pressure to all walls but does not specifically target the anterior wall.

The insertable length

The average length of the vagina at rest is 6 to 7 cm, and up to 10 to 12 cm when aroused. An insertable length of 10 to 12 cm covers almost all body types when aroused. Beyond that, the increase in sensation is marginal for most women—the upper two-thirds are sensitive only to pressure.

The diameter

Diameter determines the feeling of fullness and the pressure exerted on the walls. A larger diameter increases stimulation of the vestibular bulbs and crura through external pressure. A slimmer diameter is more comfortable for beginners or for prolonged use.

The vibrations

Krause corpuscles in the distal part of the vagina respond optimally to vibrations between 40 and 80 Hz—the same range as for the clitoris. A stable motor in this frequency range is more effective than a very powerful but unstable high-frequency motor.

Dual stimulation

75.8% of women reach orgasm more easily with simultaneous clitoral and vaginal stimulation. Rabbits and dual stimulators are designed for this combination. A rabbit’s effectiveness depends on how well the position of its clitoral arm matches the individual CUMD distance (1.6 to 4.5 cm).

The movements

Some vaginal sex toys incorporate an automatic rotation or back-and-forth mechanism to reproduce rhythmic pressure on the anterior wall. Combined with vibrations, these movements simultaneously stimulate somatic nerve endings and Krause corpuscles.

Comparison of vaginal sex toy types

Common mistakes to avoid

• Penetrating without sufficient prior arousal: an unaroused vagina is less lubricated, less extensible, and less receptive. At least 10 to 15 minutes of preliminary stimulation significantly increases natural lubrication and tissue extensibility.
• Confusing length with pleasure: the upper two-thirds of the vagina are sensitive only to pressure, not precise touch. A very long sex toy is not necessarily more effective — curvature and diameter are more decisive factors for most women.
• Looking for the G-spot as a precise point: it is an extensive anatomical complex, not a single button. Exploring it takes time, different angles, and varying pressure — not millimetric targeting.
• Worrying about not ejaculating or squirting: 42% of women surveyed in the Swedish study had never ejaculated or squirted. This is not a marker of pleasure or dysfunction — it is a normal anatomical variation.
• Using silicone-based lubricant with a silicone sex toy: it irreversibly damages the material. Always use a water-based lubricant with platinum silicone sex toys.
• Neglecting lubrication: even when natural lubrication is sufficient, a water-based lubricant improves comfort, reduces friction, and extends use without irritation.

Usage tips

• Start with external stimulation: stimulate the clitoris and vulva before any penetration — the vagina lengthens and lubricates, making internal stimulation much more effective.
• Explore the anterior wall: point the sex toy’s curve upward, toward the abdomen, at a depth of approximately 3 to 4 cm. Vary the pressure and rhythm.
• Combine with clitoral stimulation: use a clitoral vibrator at the same time or choose a rabbit vibrator to maximize the chances of orgasm — 75.8% of women reach orgasm more easily through dual stimulation.
• Always lubricate: apply a water-based lubricant to the sex toy and the vaginal opening before every use.
• Don't force deep insertion: the cervix can be painful if hit. If pain occurs deep inside, reduce the insertion length.
• Explore without aiming for immediate orgasm: the CUV zone may require several exploratory sessions before producing intense sensations — this is a matter of gradual familiarization, not effectiveness or dysfunction.

Adopt1Toy collections for vaginal stimulation

• Dildos — from classic to realistic, in all lengths and diameters
• G-spot dildos — targeted curvature on the anterior wall
• Dual stimulation — simultaneous vaginal and clitoral stimulation
• Vaginal vibrators — internal vibrations at 40–80 Hz
• Rotating and thrusting sex toys — automatic rhythmic movement
• Water-based lubricants — compatible with all silicone sex toys

In brief: how to choose your vaginal sex toy

• Prioritize curvature over length to target the anterior wall (CUV complex at 3–4 cm)
• Choose a diameter suited to your level of experience and the sensation you are seeking
• Choose a rabbit or a double stimulator if dual stimulation is preferred — this is the most common orgasm pattern (75.8%)
• Choose a stable motor in the 40–80 Hz range to effectively stimulate the Krause corpuscles
• Always use lubricant, and always start with preliminary stimulation
• Don't look for the “G-spot” like a button — explore the entire anterior wall