for a bunch of reasons
1 i guess i live up the name of this /reddit and guys tell me i look slutty so its easy lol
2 you get to see how big it is, and if he takes care of himself bc no one ever expects to fuck on the first date, and if his cum tastes good (again if he takes care of himself or not )
3 if hes big enough, then you have sex. if hes good at fucking, and kinky/into the same things as you, 2nd date
if not, then at least you got to suck dick and have fun (if you like sucking dick)
