Your mom 

1. When you have no other comebacks.

2. Also used as jokes to another when bored.

Example 1:
Your stupid!
Your moms stupid.

Example 2:
What are you doing the long weekend?
Your mom.

Your mom by Anonymous June 29, 2003

your mom 

supposed to be offensive and funny at the same time, in order for one to feel "cool" at times.

hey joey!
hey marc!
YOUR MOM!
* looks around as if cool *
dam man that was a good one

your mom by Tarayourmom December 28, 2005

your mom 

an insult to your mom usually used as a comback to other insults

-your a dick
-your mom

your mom by yo momma June 7, 2003

your mom 

Who I had sex with last night.

Your mom is amazing in the sack.

your mom by buttcheeks mcgee June 10, 2006

your mom 

used as a gay comeback

person1: what is a townie?
person2: your mom's a townie

your mom by Roscoed your mom June 23, 2004

Your Mom 

A comeback often used by rutards :

Jimmy: "Can you turn that light off?"
Philip: "Can you turn your mom off?"
Jimmy: "Can YOU turn your mom off?"

Your Mom by TuMadreYea February 6, 2010

your mom 

Person often seen on the Internet.

I saw your mom on the Internet.

your mom by MoonKnight January 9, 2003