A tan that you get on your foot that resembles a thong.

You get it from wearing your flip-flops too much in the sun. After you take you flip-flops off it your foot has a tan shaped like a thong.
*After going to the beach

Lizzy: Awww man, I just got a thong tan on my foot, nasty!!!

Mickey: Lucky for me I wore shoes to avoid getting a thong tan. Looks like a sexy tan, you got there.
by nosePIQ'r July 5, 2010
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