Your partner farts in your mouth while you're eating out their ass. You then proceed to keep the fart in your mouth and pass it to your partner via a kiss.
When you sit at the toilet and your dick is so small that you accidently piss through the gap onto your underwear and then have to wear your piss soaked underwear until you can change them
Make sure to get an erection before you urinates so that you don't start pissing your ass
Where some guys are waiting there turn at the urinal and a guy behind another because he gets pissed off and/or just for fun pisses on the ass of the guy in front of him. There he will probably have to run.