vaginal_contractions
Rhythmic contractions of the vaginal muscles, visualized as a pulsing of the female genitals.

Describes a clenching motion of the vagina seen when a character is aroused, during or after vaginal penetration, this most commonly occurs during orgasm. The biological reason for these contractions during orgasm are to massage the penis and encourage ejaculation into the vagina, increasing the likelihood of impregnation.

The vaginal contractions may be seen directly with an internal view of the vaginal canal or externally with a character spreading their labia, or after sex with gaping, showing their vaginal opening clenching. These contractions may also be shown "indirectly" with a pulsing motion of the vulva around a penetrating object or body part.
twitching pussy