A Morning After Tee Shirt is when you where the tee shirt of the last person you had sexual intercourse with the next day to work or school.
Girl 1: Ew. Why are you wearing that ugly boys shirt?

Girl 2: No. It's my Morning After Tee Shirt from Dan.

Girl 1: Oh. Makes more sense now.
by Icey0123 March 16, 2010
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