This is an act in where your significant other is eating out your asshole and then you proceed to fart inside their mouth forcing their checks to puff up like a blowfish. Then your significant other then proceeds to blow that fart back into your asshole!! If done correctly there should be a slight whistling sound!
"Dude last night I gave my old lady a sweet ass Baltimore blowfish, subsequently we haven’t made out since!”
by Jonas Olguin January 25, 2006
A classy move where a girl is giving you a rim job and you rip a huge fart into her mouth. Her cheeks puff up and then she's the Baltimore blowfish.
by Nick D September 23, 2003