twentysome 

sexual intercorse involving 20 participants
aka an orgy

some of the football team and the cheer squad got together for a twentysome

twentysome by so!id December 20, 2008

twentysixsome 

You made it a long way huh? but you still know what it means right? alright then, Vinny (not real name)

Guy: hey i just did a twentysixsome.
Guy2: cool, i’ll define it on UrbanDictionary.

twentysixsome by IHaveAGun January 3, 2023

Twentysplain

Having subject matter explained to you by someone in their early 20s who assumes they know everything and you nothing. Recipient being older than 29.

20 something: "Actually, water is not wet"

Person who gives no shits:
"Dont Twentysplain me"

20Something: "Actually Control P does that too"
Person who gives no shits:
"Twentysplaining me again brah?"

Twentysplain by Joe Nofuqs November 3, 2018

twentyfirst base 

When you browse and masturbate to every base definition on urban dictionary

You: oh man I browsed every base definition on urban dictionary last night, I got all the way to twentyfirst base

Any rational human being: wow that's pretty sad bro

twentyfirst base by Thepeepeeman October 17, 2019

Twentynine Palms 

A place in the middle of nowhere California full of nothing but Marines, crackheads, Asians and desert rats (also known as 'Cougars,' 'Desert Yetis' and 'That bitch that gave me the clap.' Generally avoided by anyone that has any semblence of a life, and loathed by most that live there. Often subjected to high winds which will hopefully cover it in sand one day.
See also: 29 Palms

Person 1: "What the hell is that smell?"
Person 2: "That's just Twentynine Palms."

Twentynine Palms by Brian Hick May 22, 2008

Twentyspeak 

is a type of spoken jargon in which consists mainly of speaking out acronyms suchs as OMG, OOC, IMHO and many others as part of a regular sentence, where in some cases it is just as easy to speak the words behind the acronym. This is most commonly used by people in their Twenties (aka millennials). Although it was originally used by hackers and gamers as "leetspeak" as a computer elitists vernacular, it's transgressed into spoken language among the millennial mass.

"That girl is so enthralled in everything MTV that I had to use urban dictionary just to understand her twentyspeak. "

Twentyspeak by rich8e8 December 17, 2009

Twentynine Stumps 

US Marine and Navy slang for Marine Corps Air Ground Combat Center - Twentynine Palms, California. It's called Twentynine stumps because it's in the middle of the damn desert and there ain't a fucking palm to be found.

"Dude, their sending me to Twentynine stumps right out of Corps School so's I can be a pecker checker to a bunch of jarheads!"
"Drink lots of water, shipmate."

Twentynine Stumps by Mister Priapus June 7, 2005