where 3 ppl, usually either 2 males and a female or 2 females and a male have sex together, lots of diff postions and is quality to do !!
by know it all February 17, 2005
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Engaging in sex acts with two other people; either MMF or FFM. Usually used in text speak.
Wanna 3sum 2nite?

Most peopl fantasise about 3sums
by freakshow July 1, 2005
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When two people have sex, And the third person video records it.
Bob: Yeah, I had a 3sum last night!
Tom: Was it good?
Bob: The third person, Was such a good recorder, It could have been a porno!
Tom: When you make it A movie, I'm buying it.
by BlahhhhhhBiiiittchh! January 15, 2010
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3 HOT HORNY SLEAZY GUYS ALL FUCKN EACH OTHER ALL THE WEEKEND LONG
Let’s have a good hot 3sum and get wired
by MR J PIG September 27, 2019
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