Before having sex, you jump onto your girlfriend's back, and whisper into her ear, "I have AIDS". She will start jumping or 'bucking' around. The aim is to try to stay on her back for as long as you can. Try to set records with your friends
"Hey man, where did you get the black eye?"
"Oh that? Well I tried out that bucking bronco thin with Sarah... she didn't think it was funny."