Reverse Birthday
A sex position in which the male re-creates his birth and rubs his head on a woman's clitoris.
I've got major chafing down there from John's hair when he did the reverse birthday on me yesterday.
Reverse birthday present
Instead of giving a gift to someone on your birthday, you expect a present instead from them.
atareh: "Devon, I know it was YOUR birthday last week, but you should still get ME something. Think of it as a reverse birthday present"