one-upper downer 

(n.) Someone who tries constantly to out-do your bad personal experiences with their own bad stories, which in their eyes, is always worse.

Me: Oh man, I just had the worst day at work! I got fired...

Tim: Oh, sorry about that. Mine wasn't too much better. I forgot to save a really long document before shutting down my computer. Such a bad day!
-----

Tim's a clear one-upper downer

one-upper downer by The Communicator November 11, 2009

one two three NUT

When u nut (orgasm) with the quickness..

bitch sucked me dry next thing u know one two three NUT! on her mothafucking face gee

one two three NUT by I C U M 1 September 12, 2010

One Man Tour-de-Force

A single person attempting and succeeding at a herculean effort, not achievable by mere mortals.

Aaron Peckham was a one man tour-de-force, creating UrbanDictionary.com and forever changing the english language all before he turned 30 years old. Unfortunately it was all down hill from there.

One Man Tour-de-Force by irrationaljared December 22, 2010

One of those hot tub nights 

when there isn't anything going on, so you and a few buddies get really drunk and hook up in a hot tub, but none of you remember the next morning.

you-"the party got canceled tonight. What are we gonna do?"
friend-"i dont know, looks like it could just be another one of those hot tub nights."

One of those hot tub nights by myriam-websters ugly twin February 9, 2012

One Trippin'

When you do whatever you have to do to avoid a second trip.

when you go shopping at the store and you have 20 bags in the trunk. You try to get all the bags on your arms and fingers to avoid having to go back out to the car.

"Went to the store and was one trippin' 20 bags into the house"

One Trippin' by Bjscho23 August 21, 2013

One Ninety-Nine 

It is a leg rub that costs exactly $1.99

One Ninety-Nine

One Ninety-Nine by Anonymous_Person_69 April 26, 2014

one eyed worm hole 

A one eyed worm hole is a never ending vagina that just seems to go on forever into the deep abyss.

"I was rooting this chick the other day, and my dick got lost in her never ending one eyed worm hole. I felt as though my entire body was being sucked into the vortex that was her one eyed worm hole".

one eyed worm hole by Mad-dawg July 4, 2014