If Dean and Anderson were to meet it would be a one night stand that all started at a bar. Not even knowing each other, but this chick made bet that Dean couldn't get Anderson and there was no way Dean was going to back down. After a few good drinks, slinging an arm around Anderson while both were red faced drunk and drunkenly staggering while singing out the door.
They try, they really do try to keep things orderly, but kisses are too wet and Anderson keeps finding himself shoving Dean's head away from the crook of his neck while shouting, "Damn it! Stop nuzzling!" with Dean responding with, "Screw you". Anderson smirks, slides a hand down to stroke Dean with a, "Come on then."
The rest is a black void as when Dean wakes up he looks around only to find bleach blond hair sticking out from under the blanket. He could think about what led him to this moment, but the pounding headache tells him to screw it and go back to sleep. He'll deal with this the next time he wakes up.