A thumbprint is a method of consuming a massive amount of lsd, where a massive (relatively, compared to a blotter dose) amount of lsd crystals are made into a small pile, pressed on with a thumb, and then the thumb into the mouth.

A thumbprint is, despite the large dose is not at a high enough level to reach levels of toxitiy in the human body.
When's the last time you had enough lsd crystals to thumbprint, eh?
by cyan April 25, 2005
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Eating so much fluff that you cease to exist. it makes you appreciate the stuff a lot more, supposedly.
A:how much blotter would be needed to equal a thumbprint?
B:aint enough in the world, man!
by anonymous December 7, 2004
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The two indentations on a girls back that look like the place where you put your thumbs when you F them from behind.
by Tejpal June 22, 2004
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Some crazy ritual the LSD cult uses to ensure loyalty of it's members. Basically it just means eating a shitload of pure LSD crystal powder so you supposedly can " see the light ", but really this is just so you stay devoted and don't rat. people who've been printed are willing to do life in the pen to protect their acid. pretty creepy shit.
go down to telegraph ave or 13th st sometime. you'll see what i'm talking about.
by rotten ralph July 27, 2004
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Sex act in the same realm of the "Dirty Sanchez" and other named acts/descriptions. A sexual act that occurs when a couple is engaged in doggy style sex. The male inserts his thumb into the anus of the female during vaginal intercourse. When she turns her head around to see what happened, he makes a poop thumbprint on her forehead.
"I was so into it when he was fucking me from behind that I barely noticed his thumb in my ass. When I turned around to ask him to fuck me harder, he gave me the dirty thumbprint."
by RHGF04 July 18, 2006
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While you are having sex with your partner doggy-style, you insert your thumb into their anus.
“Bro, I was fucking my girlfriend last night and gave her a thumbprint cookie!”
by 8M0 October 21, 2020
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The mark left from a bloody dick tip on a girl's cheek, which vaguely resembles a thumb. The blood on the dick tip is acquired from having sex with a girl on her period (hopefully unintentionally).
The girl I picked up last night didn't tell me she was on her rag so when I pulled out I left a raspberry thumbprint on her cheek.
by EmjayDub June 9, 2012
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