What is Muffin Tin?
1.
Code for someone you know who pretends they aren't gay, but acts super gay.
Did you see when Scott checked out that guy's ass - muffin tin.
See
2.
Similar to
"HA! That bitch thinks she's so hot, with all her tight clothes"
"Muffin top much?"
"Nah trick. More like muffin TIN"
See