An acronym for "Moist By Association".
Usually relates to somebody who has recently been in close contact with a moist person (eg moshpits, hugging), and is covered in someone elses bodily fluids, usually sweat.
"As soon as I got into that mosh with all those sweaty guys I got MBA straight up"
"Dude, I was just hooked up with Jan, she was so horny I think I'm MBA"
September 13, 2007