back-up, back-up prom date 

This is basically someone that you know will say go with you to prom if you ask them. This has to be a person that you can relatively stand for a full night, or else can stand to stand next while taking pictures and then ditch him/her for the rest of the night and hang out with that person that you actually wanted to come with. This has to be a person that you know no one else will want to ask, so they are definately available.

Steve is my back-up, back-up prom date, so I know that I am guaranteed to be going with someone.

back-up, back-up prom date by carolinimartini February 21, 2006

back-up

A dancefloor technique to attract the attention of a partner. Essentially this involes backing your bootie towards your partner and getting close, often thrusting. This technique will initiate a grind type of dancing.

She's backing-up to you dog! Get in

Let's get on the dancefloor dog. We can back-up on those hotties over there

back-up by Dykester January 17, 2007

up the back 

to bang someone in the ass.

She said to me, "You can go up the front or up the back."

And I thought to myself, sweet, this chick wants me to bang her in the ass.

up the back by Nick April 23, 2005

back-up channel 

There are usually "back-up channels" in which to people use in times when all other channels are on adverts. This saves people from being bored and changing activity to going outside or reading.

Dude - "I'm so glad we have this back-up channel.. i mean police camera action is pretty boring but i'm glad we're not watching some shitty adverts.
Dude-et - "yeah the adverts these days are just all for freakin injury lawyers.."

back-up channel by Jonny Clarke July 5, 2009

Back-up plan 

Keeping a person on the side as an alternative if original plan falls through.

If all else fails I've got so and so as a back-up plan, you know as a last resort.

Back-up plan by Mister please May 10, 2018

Back up the bus

in reference to being told something unbelievable or shocking, means to hold on and go back to what was just said; request to repeat and readdress a comment.

"Whoa. Back up the bus - what did you just say?"

"Hang on - back up the bus. You were doing WHAT last night?!"

Back up the bus by mypseudonym2012 September 26, 2011

Back-up Shoes

Your shoes that you keep in your locker at school just in the case of you having to poop in the stall and you don't want people to know its you by the look of your shoes .

I took a shit at school today, good thing I had my Back-up Shoes in my locker.

Back-up Shoes by Gimaf December 18, 2012