im not a line 

A line refers to the adjective, strait, so I'm not a line, would mean I'm not strait. Basically a secret way of saying your gay. Used mostly by people in the closet that aren't in a very good situation. But can also be used as a joke amongst outed LGBTQ+ members.

*Enters room with Mom*
Me: Hey mom..
Mom: Yes sweetie

Me: You are, but im not a line.
Mom: I don't understand. What does that mean
Me: Hopefully your able to understand one day but not today
*Exit the room away from confused mom*

im not a line by Cassiopeia83 December 25, 2016

I'm not a slut line 

Where a woman, presumably a slut, makes an assertion, either verbally or by actions, towards her lack of promiscuity during the course of a sexual act with a complete stranger.

Dude, she was sucking on his dick five minutes after meeting him and was then uncomfortable with removing her bra as he was moving too fast, thats a I'm not a slut line if i ever heard one.

I'm not a slut line by Slaalaikum August 20, 2009