Why do testicles draw into the body right before ejaculation?

Normal, and logical-- the balls have no roll of course in sex, they just supply the testosterone that make you want to have sex, and the sperm that is in your semen - but the sperm that you ejaculate today was produced 65 days or so. So the testicles are just hanging down there for the ride. And when you go to begin climax, the scrotum draws up tight to move the testicles up to a safer position. Because when the autonomic process of ejaculation takes place, your body has a mind of its own and most males tend to thrust vigorously and hard into the vagina. This could bruise or damage the balls if they were flopping down loose. Same thing happens when a guy is threatened or is doing heavy exercise-- the balls move up and out of the way to avoid harm. Just your body protecting the family jewels.

can't say, I know it's normal but can't say why... maybe just not to be in the middle of action with danger to be hit...