Pulsate

[Sarah]

To throb, as a pulse; to beat, as the heart.The heart of a viper or frog will continue to pulsate long after itis taken from the body. E. Darwin.

[Sarah]

When something moves by itself, like it is breathing.
A pussy that twitches and move when sexually stimulated by the mind and thoughts alone without touching it.

[Julene]

When a [girls] [vagina] gets [horny]

[Dave Paprocki]

Expand and contract with strong regular movements.

[Becky]

to beat or move with a strong, regular rhythm: