Shirt Slut

The person who goes to events only for the free tshirt

I only joined marching band to be a shirt slut

slut shirt

The shirt a slut commonly wears when she goes out to grasp the attention of guys or a revealing or tight shirt a girl will wear to a party or bar in order to show she is available and would like attention from any guy.

X: "We should go out tonight."
Y: "Yeah! I'm feeling a little naughty, I should wear my slut shirt."
or
X: "Why are all the guys dancing with that whore?"
Y: "It's because she's wearing her slut shirt."