I ACTUALLY KNOW WHY, This is 100% Scientifically proven.
I work at tim hortons, and when we make icecaps we pour the liquid into the cup and then mix them. The problem is, you can only mix or pour at 1 time because you need 1 hand to push the handle down and 2 hands to hold the cups. I've discovered that my nipples and man boobs are at the perfect height to push down the handle while my hands are free to hold the cups. THE PURPOSE OF MAN BOOBS IS TO PUSH DOWN SLUSH MACHINE HANDLES.