f.f.y.a.
f. f. y. a. is when you put your fingers up someone's butt and make them beg for mercy.
I did f. f. y. a. to my best friend and she said I was the devil.
My sister did f. f. y. a. to my brother and he ran out of the house.
At the sleepover, my friend did f. f. y. a. to her crush and it was epic.