thug-nasty thirds 

Being the third guy to have unprotected sex with a girl. Pretty high risk of STDs

If I have to wait and get thug-nasty thirds after Andrew and Roberto again, I'll probably catch an STD.

thug-nasty thirds by trojan44 February 3, 2009

Disgusting Thirds 

Having sex with a girl after two guys have already done it very recently. Even more repulsive than sloppy seconds. You are using the other two guys cum as lube.

"That chick was so hot, i didn't care it was Disgusting Thirds, i had to hit it."

Disgusting Thirds by Gashmasterken January 15, 2009

Thickshake Thirds 

theres Fresh First, Sloppy Seconds then Thickshake Thirds. Its used to describe what a womans vagina would feel like when your the third guy in line to fuck her.

Mr B to Mr P, "hey shes hot i think i'll get in for Fresh First you can have Sloppy Seconds Mr P"

Mr P to Mr B "like fuck Mr B im getting Fresh First and Sloppy Seconds your getting Thickshake Thirds!!"

Thickshake Thirds by mr kronk May 30, 2009

Five-thirds 

Used to describe something that is cool. Describes something that is "more than one hundred percent."

"Damn that snipe was fucking five-thirds!"
"Yo my rhymes are muckin' five-thirds yo!"

Five-thirds by Drew Thompson February 3, 2008

dirty thirds 

to be the third guy to have unprotected sex with a chick in a short period of time. High risk of STD's since there's 2 guys and the girl's juices floating about. worse than sloppy seconds,but better than floppy fourths

Joe likes messing with the cheap prostitutes that don't like condoms towards the end of the night and usually ends up with dirty thirds.

dirty thirds by Bobert Mcbobert June 25, 2006

three-thirds rule

A series of statistics describing the demographics of the male population at New York University. The Three-Thirds Rule states that one-third of the male population is gay, one-third is taken, and one-third is comprised of douchebags.

Chelsea: Hey, those three guys are totally hot!
Carla: Forget it, Chelsea. They go to NYU.

Chelsea: You think the three-thirds rule applies to them?
Carla: They're all wearing popped polo shirts and making out with each other when their girlfriends leave the room, so... yeah, I'm pretty sure.
Chelsea: Dammit!

three-thirds rule by placidorgasm December 27, 2010

thirsty thirds

third man in rotation on the local bust down!

al:you hear al picked up thirsty thirds on heatherlast night.
ted:yea but atleast he wanst last, word is bill picked up filthy fourths on that ho.

thirsty thirds by hep August 7, 2003