The act of yanking someones top down to reveal their
bra. To welly someone takes
alot of stealth and the
victim must be taken by surprise for it to be counted as wellying.
Guy 1: Wtf just happened??
Guy 2: I
think that girl just got wellied by her friends!
or
Guy 1: Where were you most the night??
Guy 2: I was following this girl
round wellying her... she had the biggest tits
ever!