Shrek On

A female erection "Sherection" which can be shortened to a Shrek On. This can happen when the clitoris is stimulated and full of blood, which makes it erect. This is similar to the male equivalent but naturally a little more discreet.

This would be subsequent to the term "fanny flutter"

Rachel said to Garry whilst in the throws of passion "I've got a massive Shrek on"

(Good looking guy walks past)
Rachel: He just gave me a " Shrek On"