MST

A tattoo on a female's lower back - an acronym representing "mid section tattoo" or alternatively "money shot target".

"Dude, check out the MST on that chick! I'd hit that all night!"

10 in a 5

An extremely attractive female, as in "10 pounds of party in a 5 pound bag" (kg if you're metric).

"That girl is ridiculously hot!"

"10 in a 5, dude"