To 'Crotch Out' or 'Crotching Out' is when a female sits or slouches in an unladylike fashion (often for comfort reasons), with her legs akimbo and her crotch or vagina facing outwards.
It is more frequently seen on sofas, and in the presence of close friends/other females.
A motion in which a person (man or woman, though weird for a woman), whilst in standing stance, thrusts their crotch forward and makes a downward open hand gesture with both arms at a foots length apart, down in the the crotch as it thrusts to maximum height and gesutres to oh say 'Suck It', to anyone abound and about, purely a symbolic gesture but also know to get the females moist....
mmm there's Emily Fitch from Skins seasons 3-4 I'm going to crotch pop in her Direction and see if she responds... Emily Fitch responds 'Eww, that's such a bloke thing, anyway I'm gay'. Mmmm crotch pop