Along the same lines as a puck bunny, a ball bunny is characterized as a female, mostl likely in highschool, who comes to lacrosse games for the sole purpose of hooking up with one, or more, of the players after the game. The score, penalties, and anything else relevant to the actual game is not of interest to a ball bunny.
"Man, she's such a ball bunny. I can't wait to hook up with her."