First step of three in beer pong leading to being "on fire"
After making one cup, a person may say I am pre-heating. If he makes their next shot, he will be "heating up." And if he make their next shot after that, he are "on fire"
Coined by the famous Marshall Finkelstein.
Marshall: Yo it's my first shot of the game and am already pre-heating.
Ian: Bro so am I!
Christian: Pre-heating muthafuckaaaaaaaaaaaa
by Upstanding Citizen 331 December 4, 2011
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The preparation of 420. Such as the loading of a bowl, rolling of a joint or blunt, or preparing whatever piece one may have. The process of preparing to get baked.
Steven: What are you doing right now?
Sarah: I am pre-heating in my car.

Steven: I'll meet you to get baked in a few.
by Slk16 February 5, 2015
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stocking the pantry full of munchies prior to getting "baked." (high as fuck).
larry: dude i got this new piece today, since it's 4/20. wanna go try it out?

andrew melvin: yeah man but did you pre-heat the oven?

larry: helllll yeah, niggy. i got captain crunch, chips ahoy, cheetos, peanut butter and all day hawaiin punch.
by Ryan Harrison April 19, 2011
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For men: like sloppy seconds, except the girl you're about to bang was with another girl immediately before you. Opinion is divided about whether this improves or detracts from the quality of your subsequent experience.
Don't worry about it man! She was just in there with Crystal pre-heating the oven for you, go for it!
by xag February 13, 2011
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Farting as you enter the bathroom to set the tone for the destruction about to unfold.
Brandon: *washing hands in office restroom* Hey Bill, how’s it going? Oh man, that is pungent!
Bill: Yep, just pre-heating the bathroom buddy. You may want to clear out before the magic happens.
by Hellbringer480v June 28, 2018
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