When a girlfriend/wife gets pregnant against all logic as most if not all sexual activity has been concentrated around the ass area. The assumption is that she has scooped the sperm around to the front entrance from the rear in the hope of fertilizing her eggs
Man 1: "Hey guess what, my wife is pregnant!"
Man 2: "Really, congrats man that's awesome"
Man 1: "Yeah I don't know how that happened there must have been some leakage..."
Man 2: "Either that or she's done the scooparound"