What to do when you need to fart during sex

Blame the dog.
It worked for me once.

Wait until she's licking your Asshole then Let it Rip!!

If your a guy, it will probably go the opposite direction and she may not notice depending how rancid it smells. If she does notice it will be difficult to care much in the moment and would most likely not involve any serious reaction.

If a girl farts during sex, the guy will be more likley to notice. However I have a hard time believing most guys would care much just because of how concentrated they usually are during intercourse.

Fart and laugh, then dutch oven her

Any smell or sight of shit gives me instant soft on

You'll need to excuse yourself from the room. You may or may not kill the mood but saying something, but you will definitely kill the mood if she catches wind of your dirty ass.