A child that is concieved by anal sex.
Gestation occurs in the lower intestine and the baby is born through the anal sphincter which dilates (to up to a foot) in diameter for this purpose.
I always thought anal sex was the most reliable form of contraception until i got pregnant with a butt baby and contracted herpes.
by Farmer Fife August 30, 2004
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The aftermath of a furious session of butt sex, butt babies are the resultant mix of shit and cum that is ejected from the recipient's asshole at their next dump.
After taking dick in the ass, Mattia delivered a healthy 1lb. butt baby the next time he went to the restroom.
by UvaFML November 03, 2009
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Noun; When a man takes a shit so big that it stretches out his asshole. The result is a very large stool that could be the size of a small child.
Man 1, "I took the hugest shit ever just now!"

Man 2, "How big was it?"

Man 1, "It was a Butt Baby!"
by Ronnie Kimbel February 24, 2010
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While performing sloppy anal sex with little to no care; if semen is allowed to drip from the anus into the vagina what we now know as a butt baby has the potential of being conceived. Butt babies are quite obviously identified as their overwhelming need to whine about everything and their pungent odor that will never fade.

UPDATE: Warning! It has been confirmed that a dirty toilet seat can also result in becoming pregnant with a butt baby!
Daryl: I hate that douche Scott. I can't believe he has a job here, I don't even think he is capable of dressing himself.

Bill: Dude... Scott is a butt baby, stop being so judgmental and put yourself in his poopy shoes for a hot minute.

Daryl: Oh man, I had no idea... now I feel like a butt baby.
by Cuddlesworth October 12, 2015
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The infant born that was concieved during anal intercourse. This occurs when a male ejaculates inside of a woman's anus, then she omits gas and the sperm is then forced out of and carried to her vagina. Once inside, she becomes inpregnated.
A porn stars who eats beans is most likely to produce a butt baby.
by mamabearwhiskey April 17, 2009
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n. or adj. A situation in which something bad happens.
You are such a Butt Baby man!

That was a Butt Baby thing to do..

Usage of Butt Baby via AIM or TXT = :B
by :Butt:Baby March 16, 2010
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A child born as the result of butt sex.
My boyfriend and I were doing it the "Greek Way" when I noticed something fall out of my vag. A butt baby!
by Deadbehbeh December 27, 2008
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