How to stop farting in your sleep?

Holding your farts in while you're awake can make you fart in your sleep. When you fall asleep your body relaxes and the farts just come out. Try to fart discreetly whenever you need to and that should reduce the chances of farting in your sleep. If you eat a meal shortly before going to sleep then there's a chance that you will fart in bed so there's really not much you can do about it.