Deficating in the tank of someone's toilet, rather than the bowl. Often employed in malicious context.
Suzy could not figure out why her toiled would flush only brown water. Little did she know that Johnny had upper decked that bitch the previous night.
Synonymous with "Shit." Used to express distaste or poor quality.
"This burger lastes like choon." "Get your choony-ass car out of my driveway." "Plans are choon for this weekend."