Twertle is a slang word for vagina. Pronounced "turtle" but more with a lisp. Could be used to describe a sexual encounter between two females like "twertle time." Can be used in verb context, "twertling."
In the movie Black Swan, Natalie Portman and Mila Kunis freakishly participate in twertle time.
"Don't touch my twertle!"
"I like your twertle."