Partial Unbirthing Fetishism

Partial Unbirthing Fetishism is a fetishism concerning the nearly impossible fetishism of adult head insertion into a vagina. It is much more common as a pure fantasy than in actuality.

It is an extremely uncommon fetishism but has been discussed on the internet for several decades.

In the last 3 years attempts to sub-classify it under a new category (called Endosomatophilia) were made. Sometimes it is fantasized under Vore, but was never established as a true subcategory thereof.

The following is a discussion of the reasons it is extremely uncommon in practice:

Actual Partial Unbirthing (adult head insertion into the vagina) is a fetishism that is extremely rare and probably one of the rarest of all human sexual activities. It is a curious paraphilia usually considered a true fetishism. The definition of a fetishism has changed over the years and has moved away from only requiring inanimate objects for sexual gratification to today's view that a great many varieties of less common sexual activities concentrating on body parts and even sexual organ size are now considered fetishes. Partial Unbirthing is a Fetishism in this newer and broader sense of the word.

In the real or actual practice of this it is not a form of Vore or BDSM and is only practiced by a very few devoted adult couples. One reason for this is that it must be mutually enjoyable and erotic, as it requires that the vagina must stretch to enormous size. This requires a consenting, cooperative, and extended effort between the sexual partners, with both partners considering the same fetish to be erotic -- just to start doing it. This of course is only possible where the woman has an extremely huge opening of her pelvis.

Such a huge or Justo Major Pelvis is also called "Giant Pelvis". This condition is where the minimum pelvis size is enlarged uniformly in every direction by a linear factor of 1.5, or more than the average 11 inch wide pelvis. This 16.5 inch "or more" Justo Major pelvic width is a condition that is only present in less than one in a thousand adult women.

Women of average pelvic size will sometimes hugely stretch their vaginas for purposes of greater stimulation or more intense orgasms. Also some women have a fullness fetish that is sometimes called a "bulk intromission" fetish. With gradual repeated stretching they occasionally stretch almost to the walls of their pelvic bone opening (approximately the size of a newborn's head). Those that do this are quite rare.

It is easy to see that the ratio comparing an adult head size to a newborn head size (a 21 inch circumference to a 14 inch circumference) is a 3 to 2 (or 1.5) ratio -- making this adult head size a 1.5 ratio times the 14 inch newborn head size. This ratio is just the exact same linear 1.5 ratio that a pelvis of "minimum" 16.5 inch wide Justo Major size has compared to an average 11 inch wide pelvis. For a woman with a Justo Major pelvis the 1.5 ratio to vaginally stretch to adult head size would be like the average woman with an average size pelvis stretching to newborn head size, or like this average size woman being vaginally double fisted by a man who has fairly large hands.

A well known government Hispanic study included the anthropometry (scientific measurement) of nearly 5000 adult women using anthropometric calipers to measure the largest pelvis at 19 inches biiliac width (side-to-side bone width). This made her 19 inch wide Justo Major pelvis have a huge 1.73 ratio when compared to the average size pelvis of only 11 inches width. This was even a larger size pelvis than a pelvis of "minimum" Justo Major size (that requires at least a 1.5 ratio). If a woman with a pelvis of this very large size were to do the same vaginal stretching practice to near her bone opening size, she could then vaginally take inside her vagina a huge 24 inch adult head. That size head would be 24 minus 21 inches, or 3 inches, larger than the 21 inch circumference adult head that a pelvis of the minimum 1.5 ratio Justo Major size pelvis could potentially stretch around. This larger size 19 inch wide pelvis would require a lesser degree of stretching to be comfortable when taking inside a 21 inch (much smaller size) adult head.

This degree of comfort might be comparable to a woman of average size being vaginally double fisted (see fisting) by hands of considerably smaller size, or even being fisted by just one large hand. This less common but larger size pelvis (one in five thousand) Justo Major pelvis would have a sufficient size to potentially make partial unbirthing much easier to achieve. This 19 inch wide pelvis (measured in one out of the 5000 women) was a Justo Major pelvis that was indeed of huge and rare size.

The above merely illustrates how rare a sufficiently large pelvis would be in order that gradual and often repeated vaginal stretching practice might comfortably reach a partial unbirthing size. Some women find large vaginal stretching quite easy and enjoyable, but others do not. The rarity of this fetish is further compounded by how few such women with this huge pelvic size would be motivated by the fantasy and potential stimulation to devote the weeks or sometimes months of stretching practice with no assured guarantee of success. Also, the rarity of her adult partner, who wanted to work with her in many repeated sessions to help her gradually stretch, and who wanted to do partial unbirthing in a safe, erotic, and mutually enjoyable manner has to be considered. Two people, both dedicated to the same rare fetish makes the practice less common.

When the pelvis is less than a Justo Major size (or < 1.5 times the 11 inch average width), with the exception of small midget heads, such a fetish could never even be considered -- as bone will not stretch. Only a very few confirmed instances of adult vaginal head insertion are even known.

It is estimated that less than one in a million sexual partners have actually done partial unbirthing making it a very very rare human sexual activity.

Illustrating the usual position used for Partial Unbirthing in the "Joke Type Internet Encyclopedia"... so this is only useful to show the position used and the relative size of the Justo Major pelvis required and not any verifiable, real and extremely rare images, see:

http://www.encyclopediadramatica.com/index.php/Partial_Unbirthing

Stories, see: http://www.asstr.org/~A_Nony_Mous/