What is Y.b.s.m.?
Your Boobs Squirt Milk
person 1: 'OH my gad, Y.B.S.M.'
person 2: 'What?!'
person 1: 'Your top.. there's a white liquid on it..'
person 2: 'Oh. yeah my breasts tend to squirt milk..'
person 1: 'eww.'
See boobs, milk, squirt