When you're at the fire hall droppin a dookie, and an emergency call lights up the bell, so you gotta pinch it off, turbo wipe, and run to the rig just as they're ready to head out.
FF "Sorry guys, I was midpush and had to make an emergency shit pinch."
CAPT "Did you wipe? Holy shit that stinks!"
Where you insert one finger into the Anus and the thumb into the vagina of a woman and proceed to 'pinch' the thin membrane between the two areas chasing the woman to orgasm.