"I blow out first ..."

This evening I happened to listen to a conversation between two teenage boys in men's locker room in a gym. I will refer to them as B1 and B2.

B1: listen I've a question. My girl friend blow out a lot. Do you argue with your girlfriend very often?
B2: We do.
B1: like on big...big issues?
B2: We even argue on every little issues
B1: Who blows out first?
B2: depends. If I didn't eat I blow out first. lol