I would not take the words "Bite Me" on the front of this T-shirt as referencing the breasts. I would think that it meant Bite Me in general, as a provoking statement, like I don't care leave me alone. And the fact that it was a vampire is what the twist would be. The twist or joke would not be that it is referencing the breasts. Because then that would be two twists- the vampire thing and the breast thing. And that is just too much for a T-shirt to take on at one time!
I guess it could come from a sort of sexual place if one sees vampire biting as a sexual thing.