1. A female whom one is not in a relationship with, but is currently or potentially having sexual relations with.

2. A casual sex partner.
Where's the sex girls at!?
by Ryan Hives December 10, 2007
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When a female engages in every sexual manuever except sex its self.
man all i got was a hand job she was a but sex girl.
by sebs2020 October 24, 2011
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The term used for an act of hetrosexual males replicating the intimate and affectionate nature of females (usually incited by estrogenically driven excitement and joy) with one another, including but not limited to: hugging, rear grabbing, compulsive giggling, breast fondling etc. Most oftenly used by males as a source of humor and slight means to bond. The inverse of this is boy sex to females.
TJ: Dude I haven't at the beach in so long!
Ricky: I'm so stoked! (Splashes TJ and Hawk)
Hawk: If we were girls, we'd be having sex with one another!
Ricky: ...girl sex.

(Hawk and Ricky proceed to splash each other and TJ and giggle like women)
by Rocknight September 21, 2011
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sex between females; while often referred to as Lesbian sex, it is not appropriate to. Lesbianism is a sexual orientation, not physical sex between two women. Fantasizing about having sex with another woman does not make you a lesbian. Women are usually seen as soft, gentle, loving, and romantic, which is not how men are usually perceived. A woman may desire these things in her sex life. She may feel that since a woman has the same anatomy, she will be a better lover and more in tune with her needs. Even though a woman is not sexually attracted to other women, she may be attracted to these "feminine" qualities. To a certain extent, female/female physical intimacy is socially acceptable, at least when not done to exclusion.
Nancii and I enjoy intercourse, mutual masturbation, and oral sex, but she still needs her girl-girl sex once in awhile with "S"
by Jake February 18, 2004
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"That girl stayed at Mark's place last night."
"Ewwww..Mark is having fat girl sex
by Lunch is free on Tuesdays August 21, 2008
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