While I'd love to sit here and put this as eloquently as humanly possible, there's really no use for such bullshit niceties—basically, when it comes to sex, shit happens (sometimes quite literally, but no worries, we're not going there—not today, anyway).
When you think about the act in its most basic form, you're taking two humans, throwing them together all naked and sweaty, adding a heaping load of awkward limbs and strange fluids, and voilà! Sexy, right? Ah, quite the contrary. There's actually nothing sexy about sex when you reallllly think about and that's why the aforementioned shit happening needs to be acknowledging maturely. There's no room for laughter or poking fun, especially within couples. We've all had uncomfortable moments between the sheets and while I understand it seems easier to bury your head under the pillows and never come out, you have nothing to be ashamed of! We're humans—we're flawed, our bodies make noises, get over!
If you can't get it up, don't let yourself get down! Maybe you drank too much, maybe you're feeling stressed, hell, maybe you're just not in the mood. Whatever the case may be, just know that if your partner is making you feel bad over this particular "appendage failure", you shouldn't be with them.
If a little gas slips out. Gross? Yes. Perfectly natural? Also, yes.
If you're girlfriend gets her period. It's blood, not a sewage pipe explosion, all parties involved WILL live, I promise.
Basically any accidental pee isn't the end of the world. Bladders work in mysterious ways.
Queefing....ugh, I hate the word. It sounds so much worse than it is! It's trapped air! Move on!
Bumping heads/teeth/knee caps/etc.—remember, two humans, two bodies, lots o' uncoordinated limbs.
Miscalculating the trajectory of your....spunk. Hopefully you avoid the eyes, because I hear that can be painful, but the forehead or the hair isn't the worst thing in the world, sort of like a leave-in conditioner. Too fair? Nah, never too far.
If you finish too soon. Often times, the female will take it as a compliment that you her so attractive you couldn't help yourself. Chances are you're just selfish in bed, but we won't tell anyone.
Body odor. Sweat builds, sweat smells—simple as that.
Rogue pubic hair in the mouth. A bit stringy to be sure, but nothing to write home about.
If you can tell she's faking it, don't freak out. If it's not an everyday occurrence, just leave it be. I'm sure she was just tired and trying to spare your feelings. If you notice it persisting, then yes, address it.
Charlie horse/pulled muscle/body part falling asleep—these are likely to happen the older you get and ultimately are just signs of the hard work and effort you're putting forth. If anything, sex is the most ideal way to throw your back out or strain your neck, right?