on the side 

Having an extra sex partner. Having sex with a friend as in friend with benefits while in a relationship with someone else.

I like fucking him on the side, just like I like ordering my salad dressing on the side.

on the side by Frisco Stories October 8, 2008

on the side 

Having a sexual relationship with a person outside of one's primary, emotional relationship.

See, mistress.

"Hey man, I heard you were getting a little action on the side! Did you nail her?"

on the side by Nathan V. October 1, 2008

On the side 

weekend, the days on the sides of a calendar i.e. Saturday and Sunday.

Person 1: Hey what're you doing on the side?
Person 2: I'm going to Lake Taho with Matta dn Jess.

On the side by Nikkola March 6, 2005

on the side 

Gay, opposite of being straight.

That dude wearing the tight nipple shirt is on the side.

on the side by mattoincapace October 24, 2005

on-the-side 

a) someone's sidekick

b) an offensive term for someone's mistress or lover

If you want an on-the-side definition b), don't be in a classical ltr; look for an open relationship instead.

on-the-side by Uncle Dimma June 5, 2015

on-the-side 

a) humorous, someone's sidekick

b) (very offensive): someone's mistress or lover.

I'd rather have an on-the-side definition a) than an on-the-side definition b)

on-the-side by Uncle Dimma December 8, 2014

on-the-side 

a) someone's sidekick
b) an offensive term for someone's mistress or lover

If you want an on-the-side definition b), don't be in a classical ltr; look for an open relationship instead.

on-the-side by Uncle Dimma March 6, 2015