Farting

Farting , also known as flatulence or "blowing off", was a bodily process that affected some species, involving the expulsion of gas.

Biology
According to Luke Smith, it was a "normal process of the human bowel." Silent but deadly was a type of fart. (TV: Aliens of London, Revenge of the Slitheen) Ingestion of food such as cabbage, (TV: Revenge of the Slitheen) and baked beans, (TV: The Bounty Hunter) could induce it, as could feelings such as stress (AUDIO: Sync) and excitement. (AUDIO: Madquake) Farting could also be a cause for relief; indeed, some Slitheen were heard to express relieved groans after letting off a fart. (TV: Aliens of London, AUDIO: Madquake)

Culture
Farting was often frowned upon by humans, due to its foul smell and loud noise. Many humans, however, thought farting humorous. (TV: Revenge of the Slitheen) Sayings associated with farting included "[they] who smelt it dealt it", "[they] who said the rhyme committed the crime" and "[they] who said the verse made the atmosphere worse." (TV: From Raxacoricofallapatorius with Love)

Among the Raxacoricofallapatorian species
When members of the Slitheen family used compression fields to fit themselves into human skin suits, it caused a condition called "gas exchange" which was similar to farting but with a smell like bad breath. This was due to calcium decay as Raxacoricofallapatorians were a calcium-based species. (TV: Aliens of London / World War Three) A gas exchange unit was a piece of technology worn by Slitheen. (AUDIO: Madquake) They eventually solved this problem, as well as becoming able to fit into slimmer skin suits. (TV: The Lost Boy)

When Blon Fel-Fotch Passameer-Day Slitheen, in the form of Margaret Blaine, took Cathy Salt to the toilets 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.". (TV: Boom Town)

A Slitheen disguised as Ambassador Rahnius, who arrived in Sarah Jane Smith's attic to apparently reward her and friends, was exposed by his uncontrollable farting, despite blaming it on his chair. (TV: From Raxacoricofallapatorius with Love)

The naked Leef Apple Glyn Slitheen-Blathereen farted while eating Shepherd's pie cooked by Clyde Langer. Later on, Sarah Jane had Mr Smith replicate the sound of an alarm bell to destroy the Rakweed in Leef and Tree's stomachs, causing a massive methane gas build-up which killed them both, exploding and covering Sarah Jane's attic with their remains. Clyde Langer noted that they had "farted themselves to death." (TV: The Gift)

The naked Bella Slitheen let off an exceptionally long and loud fart without her gas exchange unit, which she attributed to being "really really" excited at the prospect of a human hunt. (AUDIO: Madquake)

Other instances
According to Rose Tyler, cows farting methane into the atmosphere was one of the causes of global warming on Earth. (AUDIO: The Flood)

Farting was still possible after death, as the living dead man Owen Harper discovered shortly after being brought back to life by the resurrection gauntlet. He mourned in advance his last fart, saying that, along with sex, he'd miss it. (TV: Dead Man Walking)

The governor of Justicia's obesity and flatulence led Rose Tyler to believe he was a member of the Slitheen family in disguise. She attacked him, but soon discovered he was just a large human. Later, Lazlee Flowers inadvertently revealed her presence to Ermenshrew Blathereen when she farted. (PROSE: The Monsters Inside)

When Victor Kennedy absorbed Bliss, her face ended up on his right buttock. When Elton Pope asked where she was, Kennedy lifted himself up, farting as Bliss told him he didn't want to know. (TV: Love & Monsters)

After the Tenth Doctor absorbed rontgen radiation he said he needed to expel it out of him and then farted. (TV: Smith and Jones)

Having experienced a sudden bout of stomach trouble as part of the Adipose necklace-induced full parthenogenesis, Stacy Campbell suffered a loud fart on the moment of her death as she exploded into a pile of Adipose in her bathroom, which was witnessed by Donna Noble. (TV: Partners in Crime)

The living Mona Lisa painting claimed that her model "farted like a donkey." The animated painting also asserted that her so-called enigmatic smile was due to her model experiencing wind during the portrait sittings. (TV: Mona Lisa's Revenge)

The Vykoids disguised their ship as a mammoth which, as encountered by Amy Pond and the Eleventh Doctor, was notorious for its farting. (PROSE: The Forgotten Army) Clyde Langer farted while facing off against a Slitheen disgused as Ambassador Rahnius. (TV: From Raxacoricofallapitorius With Love)

Sam Swift the Quick once quipped that the Twelfth Doctor was so old, he "farts dust". (TV: The Woman Who Lived)

Other references
Clyde Langer commented to Maria Jackson that the claim of what were apparently Luke Smith's real parents "[stank] like a Christmas dinner fart". (TV: The Lost Boy) Among the jokes he told in order to use laughter to defeat the Pied Piper was "What's invisible and smells like carrots? Rabbit farts." (TV: The Day of the Clown) Clyde later commented that an old shed next to Ashen Hill Manor smelt like "cucumber farts". (TV: The Eternity Trap)

Behind the scenes
Several stock farting noises are played constantly alongside quotes by Blon Fel-Fotch Passameer-Day Slitheen in the web-based game Slitheen Surfer. In Monster Match, a fart sounds when the player matches the Slitheen.

John Barrowman and David Tennant used to hold fart contests much to the annoyance and disgust of Freema.

In the Doctor Who Farted sketch from Family Guy, the Tenth Doctor broke wind in his TARDIS.