the sex face and other embarrassing natural occurrences...

It's a sad fact of human nature that when we are in our most intimate moments we make faces that... well, that defy description. We may also sweat, moan, sigh, grunt, scream, squeal, squeak, and there are other things too. Things I won't even get into. The fact is sex would be gross and comical if we didn't like it so much.
Actually, it gross and comical even when we like it so much.
And sex isn't the only activity in which we engage that makes us look and sound ridiculous. Watch the face of any athlete pushing herself to go further, faster, harder. That's not a pretty face. The face made when someone sucks on an especially tart lemon? Or takes a shot of cheap tequila? The yelp of pain a human voice can let out upon a tiny injury like a paper-cut or stubbed pinkie-toe. Or the wail of agony a man may let out when his favorite team loses some very important game.
All of these are downright pleasant, I fear, when compared with the face I make as I sing along half under my breath while playing Just Dance... There's a reason I don't sing and dance in public.