SHLICK / SHLICKING
Schlick, or schlicking, is the sound supposedly made when a girl/woman masturbates. Urban Dictionary has recorded its usage as a slang since 2003.
The name derived from Japanese comics not long after the word FAP was invented (Fap is the word used for male masturbation sounds in Japanese comics).
Shanon Lee: I want to play with myself...
-SHLICK SHLICK SHLICK-
Shanon Lee: Ahhhh.. that felt great!