Farting

Flatulence, often referred to as farting, was a bodiliy process affecting Humanoid species, involving the expulsion of gas out of the rectum. Flatulence was frowned upon by Humans, due to its foul smell and loud noise.

When members of the Slitheen family used Compression fields to fit themselves into Human skinsuits, it caused a condition called "gas exchange" which was similar to flatulence but with a smell like that of bad breath. This was due to calcium decay as Raxacoricofallapatorians were a calcium-based species. (DW: Aliens of London,World War Three)

Flatulence was still possible after death, as Owen Harper discovered shortly after being brought back to life by the resurrection gauntlet. (TW: Dead Man Walking)

Many people considered flatulence to be humourous. When the Abzorbaloff absorbed Bliss, her face ended up on his right buttock. When Elton Pope asked where she was, the Abzorbaloff lifted himself up, farting as Bliss told him he didn't want to know. (DW: Love & Monsters) When Blon Fel-Fotch Passameer-Day Slitheen, in the form of Margaret Blaine, took Cathy Salt to the toilets in order to kill her, she noted her "little tummy" was "complaining" when she farted loudly. Soon after, when she farted after entering the toilet, Cathy remarked, "Sounds like we got here just in time.". (DW: Boom Town)

In one parallel universe, the natives of Tersurus communicated through carefully controlled "gastric emissions", and became extinct when they discovered fire. The Doctor told the Master in the Tersurans' language that the Daleks were planning to betray him. (DW: The Curse of Fatal Death)