He's yelling "I'm going to come, I'm going to come!" While 90 per cent of you is internally shouting HHHOOOORRAYYYYYY!, there's ten per cent of you that knows it's time to decide what to do. It's the ultimate decision to make: spit or swallow? While it was all very naughty and fun talking about these things with your friends when you were 16, it's all put into perspective when he shoots his load into your mouth and you're left with a gobful of semen which you're not sure what to do with. All those wriggly wet spermies with no where to go. Swallow it? Hmmm, it's pretty gross though. But it's cleaner, right? Or you could leap up, ruin the moment, and spit the whole lot into the nearest tissue/bin/sink, pray he doesn't notice how disgusting you are, and run back to bed afterwards with the frail hope that now he's going to return the favour and go down on you in the most glorious way possible.