The foldy is preformed when a intoxicated gentleman can't acheive wood, even after oral stimulation. So naturely he folds his flaccid manhood and inserts it into the woman. Its half the length but twice the width and triple the fun.
Marty: Hey bra you were fucking wasted last, night did you fuck that slappa
Ryan: Yeah bro, you know how I roll! I was so fucking messy I gave that bitch the foldy!!
(usally followed by high fives, and cheering)