This is a rite to make a person of your choosing fart vehemently. I discovered that spell in an old grimoire about Rune Magick. I adopted it slightly for a more modern use.
You will need some material to draw or cut the runes on and either blood or red paint.
First create a bind-rune of these runes:
Perform some sort of opening rite.
Draw that bind-rune on your basis. First ansuz (reversed), then naudhiz and finally thurisaz.
While drawing that runes, chant their name and what they should do:
Ansuz: Ansuz I write thee (name), that will plague thy belly with great farting
When you've done this say:
May it loosen thee (name) from thy place and burst thy guts. Thus is my will
Channel some energy into the runes while you cast them. Then merge them together and send the spell off.
Perform a banishing rite.