your sister 

The person all your guy friends want to fuck when they realize she isn't just yur little sister any more- she's your little virgin sister who is hot now that she has boobs and shaves her legs.

"Damn! Your sister is hot! When did that happen!?!?"
"Dude as your best friend, would it be weird if I fucked your sister?"

your sister by Sexy Stephy June 6, 2004

Your sister 

Its a more recent variation of 'your mom'. is often used to insult somebody with or without a sister. used more often now as your mom is becoming out dated. (still only used by douche bags)

first guy: i heard a noise last night what were you doing?
Douche bag: your sister
surrounding audience: OOOOOOOHHHHHHH!
random guy: i like turtles
2nd douche bag: i like your sister
. . .

Your sister by turtles are big March 1, 2011

your sister 

One hot piece of ass. Penises can be found in her mouth, pussy, and ass.

Damn, your sister is hot!

your sister by Crackalac July 1, 2003

Your sister 

Someone doing ur sister

Billy: what are you doing?
Nate: your sister

Your sister by Welcum May 30, 2018

your sister 

another name for a person who you "realy like" and want to tell joke about without her knowing...

look how much your sister is eating...

your sister by babag March 31, 2005

Your sister 

An absolute bitch that slaps you in your gob every time she sees you.

Shouts about her friends and her boyfriend

Friend:Your sister just kissed your boyfriend!!!
Me: what a bastard!

Your sister by DarkAngel1 May 11, 2019

Your Sister a Mister

Only used by the almighty, worse then your mom gay and everything else

Caleb:Your mom gay
Kyle:Your dad a lesbian

Caleb:Your granny tranny
Kyle:Your gramp tramp
Caleb:I'm sorry but you have insulted my to my boiling point and now I'm afraid I have to use a forbidden phrase upon you
Kyle:Do it pussy
Caleb:Your sister a mister
Kyle:Just fucking melts

Your Sister a Mister by NippleringBitch March 15, 2018