When dealing with your guy's cum, it's all in the face. There are many other important factors, obviously, but if your face looks weird that's not going to work well. He'll cum. He won't likely say anything. But he'll notice the difference when he's jacking off to porn. Weird faces don't take porn stars very far. And if something doesn't take a porn star far, that's the smoking gun that most guys agree.
Having fun with your guy's cum is a major turn on. Eva Angelina does this amazingly well as shown here. At 10:50, she's all smiles. Ready to have fun with his cumshot. Eyes open. Looking at either him or his cock. I think guys tend to like it more if you look at their cock more often than the eye contact thing, but that could just be a matter of personal opinion.
And here's a great example of a terrible face that ruined an other wise good fucking sesh. Skip to 25:10 to see what I'm talking about.
So bottom line, don't close your eyes the whole time (or at all, really). Don't make weird "I'm letting you cum on my face but I'm not excited about this" faces. Don't act like you're down for him to cum on your face, only to creep back a few inches so his cum gets less on your face. Don't stop breathing through your nose and sounding like a geek with a cold when you lick his cum up. Guys notice these subtle nuances. More than we would ever think.
