I'm looking for an HP fic I've read only once before and I'm pretty sure it's Harry/Draco. All I remember clearly about it was that it was slash and
that the boys in it wore panties and fucked each other without taking them off. The guy on top sort of just pushed the panties aside and pushed his cock inside designated bottom's ass, amid much moaning and groaning and breaking of the third commandment, i.e, taking of God's name in vain.
Ring any bells?
ETA: Found! It's You Shouldn't Have by
cursescar.