shack prize
a piece of clothing that you obtain as a result of spending the night at someone's place, or them spending the night at your place.
"Damn...where did you get that serape?
"It's a shack prize from that guy who I met last Saturday at the Cinco de Mayo party. He forgot it when he snuck out on Sunday morning."
"It's a shack prize from that guy who I met last Saturday at the Cinco de Mayo party. He forgot it when he snuck out on Sunday morning."