Toilet humour

Public reference to bodily functions such as urination and defecation is taboo in many cultures and thus arouses intense anxiety in many people. For this reason, there is a whole sub-genre of humour, toilet humour (also potty humour or bathroom humour) based around excretion. This genre is particularly popular with children.

Many artists have made their names promulgating toilet humour:

Much of the lyrical content of avant garde rock musician Frank Zappa's songs revolved around toilet humour, for example, "Watch out where the huskies go, and don't you eat that yellow snow" (from the album Apostrophe).
The humour of the animated series South Park also consists largely of toilet humour, even going so far as to have a talking piece of excrement as a recurring character.
Dr. Slump, a manga from Akira Toriyama (the creator of Dragon Ball), also had a strong scatological bent.
The Private Eye comic strip Barry McKenzie written by Barry Humphries and drawn by Nicholas Garland are a treasure trove of chundering, parking the tiger, splashing the boots, and draining the dragon, with much of the allegedly Australian slang created by Humphries himself.
Ubu Roi by Alfred Jarry, translated as King Turd, opens with the line "Merdre!" (translated as "Shitter!") and is filled with scatological humor. Now regarded as one of the first examples of the Theater of the Absurd, Jarry was only 14 years old when he began it as a spoof of one of his teachers.
The adult comic magazine VIZ has, over 25 years, built a publishing empire from toilet humour.

Toilet humour also refers to jokes around modesty, such as if one is seen naked or in his/her undergarments. It can also refer to jokes revolving around the incontinence of infants and young children or the aged or infirm. Jokes about wedgies and tighty-whitey underpants also fall in this category.

Constipation is another source of toilet humor. Screamin' Jay Hawkins recorded his "Constipation Blues" with his trademark yells after his first bout with blockage and the Bonzo Dog Band recorded "The Strain" on the same topic and with many of the same sound effects.

Euphemisms and witticisms

Many forms of toilet humour involve euphemisms for excretion, such as the following:

Urination

Shitting Piss Ass Fartclown
Freshen my Snapple
Bleeding the Lizard
Breaking the seal
Change water on the goldfish
Do a wee
Draining the dragon
Draining the main vein
Draining the radiator
Draining the one-eyed monster
Draining down the system
Go pee pee
Going to see a man about a dog
Going to water my horse
Leak the lizard
Lower the water level
Number one
Pass water
Piddle (considered a coarse expression in some quarters)
Pit stop
Pointing Percy at the porcelain
Punish the porcelain
Release the pressure
Refresh the body
Relieve yourself
Seeing a man about a dog (or a horse)
Shaking hands with the vicar
Shaking hands with the wife's best friend
Shaking the dew off the lily
Siphon the python
Spend a penny
Sprinkle
Steering Stanley to the stainless steel
Syphon the python
Taking a leak
Taking a pee
Taking a piss (considered a coarse expression in some quarters)
Taking a slash
Taking a whiz
Tinkle
Training Thomas on the terracotta
Twinkle
Visit Uncle Charley
Void my bladder
Going to walk my snake
Water my weasel
Write my name in the water

Defecation

Taking a Ron Jeifler
Faxing a shit to the toiletmachineberg
De-corking the borking
Dropping the Mexican Boll Weevil
Drinking From the Goblet of Man Love
Squirt juice
Hungry Hungry Hippos
Assfire
Cripping A Crapple
Monopoly!
Tuesday Afternoons
Poop McFartlene
Dr.Benjamin Fartlin
Giving birth to the black eel
Backing the big brown motorhome out of the garage
Dropping a dook
Releasing a depth charge
Doing some spring cleaning
Back one out
Blasting a dookie
Boo-Boo
Ca-Ca
Curling one off
Cutting rope
Poo-Poo
Doo-Doo
Doodey
Download a brownload
Dropping anchor
Dropping the weights
Dropping a bomb
Dropping a deuce
Dropping a hoopsnake
Dropping a jolst
Dropping bass ("base" as in the opposite of treble. Not the fish.)
Dropping some friends off at the pool
Dropping the Browns off at the Super Bowl
Dropping the kids off at the pool
Feeding the seagulls (politer version of "Feeding the shitehawks")
Filling the bowl
Giving birth
Going Boom Boom
Going poop
Launching torpedoes
Laying a brick
Laying a cable
Laying a Hank
Laying a turd
Lose some weight (Also used in urination)
Making a tail
Making logs (or a log)
Making waves
Makin' bears
Number two (a portable toilet company advertises itself as "Number One in Number Two".)
Pebble-dashing the porcelain
Pinching off a loaf
Pinching a yam
Strangling a darky
Taking a brew
Taking a crap (see also Mr. Thomas Crapper)
Taking a dump
Taking a poo
Taking a shit (a coarse expression, not a euphemism)
Taking the Browns to the Superbowl
Taking the Cosby kids to the pool
Taking the morning curl
Unloading a batch of cigars
Poopy Woo
Going to meet Jim Davidson

Flatulence / Farting

Let one off
Launch one off
Let one go
Explosion between the legs
Killing the barking spiders (helps if you stomp)
Letting the Wookie win
Blowing out the colon
Anal thunder
Ass-music
Fart
Beef-cloud
Blow a big one
Blow off
Booty burp
Break wind
Churning urn of burning funk
Bust ass
Choke a donkey
Crop Dusting (while walking)
Chemical warfare
Cut the cheese
Drop one's guts (as in "Who dropped their guts?")
Erupting the anal volcano
Give birth to a brown baby ghost
Grunt (as in "Who grunted?")
Honking for clearance
Launching a growler
Let off a howler
Let off a stinker
Rip one
Man Queef (Extremely vulgar)
Message from below
Number four
Pass gas
Pass wind
Dirty bomb
Trouser cough
Woofie

Vomiting

Barfing
Be the mother bird
Blowing chunks
Bow down before the porcelain god (On some occasions, the worshipper vows to the god never to drink again.)
Calling Huey (or Ralph) on the big white phone
Catch it on the rebound
Chow
Chunder
Cook up a pavement pizza
Cry Ruth
Date Porcelain Patty
Driving the Buick to Europe
Driving the porcelain bus
Feed the fish (when seasick)
Feed your young (like a mother bird regurgitates food for her chicks)
Food Escape!
Hurling
Jackson Pollock
Lose your lunch
Make a hideous jiffy bag
Make like Mount St. Helens
Number three
Paint the sidewalk
Pray at the white temple
Ralphing
Regurgitate
Reverse-drink (from the Thunder Mug)
Revisit dinner
Park the tiger
Pulling the trigger (intentionally vomiting)
Puking
Snow bank pizza
Soul coughing
Spewing
Splatterhouse
Spraying McDonalds (as in "Did somebody spray McDonalds?")
Talking on the porcelain telephone
Talking to the weeds
Technicolour yawn
Throwing up
Un-eat
Upchuck
Yakking
Yorxing

Ambiguous

The following are used as intentionally ambiguous terms for a visit to a bathroom/toilet to urinate, defecate, or both:

Finishing up some paper-work (wiping)
Going to hit the head (Naval Term)
Going to the can
Going to the little boys'/girls' room (mostly in American English)
Going to the loo (UK)
Going to the bathroom (US)
Going to the "office" (or "cubicle")
Going where even the king goes alone
Going where even the emperor must go on foot
Paying a visit
Powdering one's nose
Taking a biological break
Taking a constitutional
Using the facilities
Using the plumbing
Answering nature's call
Seeing Mrs. Murphy
Visiting Mr. Limbaugh