Sticking your head in the bog (toilet) and flushing the chain. Apparently also known as a 'swirlie' in other parts of the world.
Occurs mainly in school and administered by bullies.
by Footle July 15, 2005
A sexual act whereby the male/female decides to unload both the solid and liquid forms of waste from themselves onto thier partner, at the same time, thus giving the same effect as a traditional "Bog-Wash".
Oliver: You'd have sex with that beast of a girl Claire?!, i'd rather take a bog-washin' off Vanessa Feltz!
by J May 4, 2005
Old-school definition:

When dumping out, a turd hits the water at high speed, usually because of the gas build up behind it increasing velocity. This causes the toilet water to splash, sending toilet water up your butt hole. A very uncomfortable mental and physical reaction because you realize that bog water has shot up your ass.
OMG, I took a power shit and got bog-washed. Now I have bog water up my ass. I'm glad I was at home, and not on some some nasty 7-11 toilet. Need to force a shit to get it out of there!
by The OriginalPsychoMike April 11, 2016
Said for something that someone says. Like when someone talks just to say something even though they're totally clueless about the subject, they really really, really, want to contribute, and so, just come up with arbitrary stuff to feel smart and/or included. Typically the contribution is a borderline delusional thought.
hey did you hear about the mars rover successfully finding clues on past water activity?

yeah man, some interesting findings 4 sure.

hey yeah dudes! they found water out there, heard they'll have the rover dig wells in preparation for human exploration, they're going to cover up the wells with tarp while they work out what to do about a biosphere.

What!?! bog wash dude! you OK?
by May 17, 2017
While having sexual intercourse "doggie style" over a toilet him/her shoves the others head in toilet.
dave: yo you muck that bitch last night ?

Kyle: aww ya bro! gave that slut a bog wash, nearly drown that bitch
by Rbuds August 25, 2017