When you spend all night buying pay-per-view pornos and rub the pope all night long. You eventually pass out and in the morning when you wake up your sheets are all crusty from your spooge.
Guy 1: Hey man what's going on?
Guy 2: Oh, you know, putting clean sheets on, dusting the mattress.
Guy 1: That's bullshit you spent all night jerkin it and now you have Morning Crust.