Okay, since I'm allowed to know this tradition (and the parents LOVE to see it also) I guess I'll tell ya one of my bf's chapter. After one of the brothers pin their girlfriend, well, they get thrown in the lake behind the campus. This is of course after singing to the girl then the guy get's it.
But, as far as I know, no other gf has jumped in after them...I'm tempting to be the first...maybe start a new twist on the tradition?