Typically used with the preceeding pronoun "her", a metaphor used when having sex/nailing/fucking a girl (commonly referred to as a slut, hoe or bitch) so vigorously that you could visualize splitting her in half up the centre (or up the back, respectively). Usually referring to a slim tall girl, or a cute, tiny petite one.
Often used in the degrading sense by a male among his peers to raise his esteem.
"I picked up the hottest slut at the bar last weekend: she was blonde, fit body, tight ass; the works. We're going out for drinks tonight :D.... I cant wait to take that bitch home and break her in half!"
grindin'dirty dancingdry sex When a boy and girl grind on eachother, the girl presses her ass into the boy so she can feel his penis through their clothes. The boy pushes her head down to resemble him banging her from the back. The girl will normally shake her ass to try and arouse her partner
Erika pushed up on Danny and he put her head down and was practicly bangin her from the back.
Jack: "Damn Danny you know how to break her off."