The vulva of preadolescent girls appears to be positioned farther forward than that of adult women, as you can see a greater percentage of their labia majora and pudendal cleft when they are standing. This gives you the impression that the vulva moves, rotates, backwards toward the anus during puberty. The vulva does not actually move. What happens is, the formation of this mound of fatty tissue causes the forward portion of the labia majora to be pushed out away from the pubic bone. When a woman in standing, this results in her labia majora being pushed downward, becoming parallel to the ground, and out of sight when viewed from the front. Women with very little body fat may not have a pronounced mons veneris, resulting in their vulva appearing to be located further forward than that of other women. The opposite is true of women with high concentrations of body fat. The position of the clitoris, and urethral and vaginal openings are defined by the bones of the pelvis.