These are the three explanations I got over the last month (the song is very popular at my school with the sports guys, for some reason.) :
1. Tying a bitch to a bed (hands, I assume) and fucking the hell out of her
2. Putting the bitch on the bottom and lifting your arms and legs up...?
3. Doggy style fucking, cum, then stick a piece of paper on her back --> cape.