You have intercourse with you’re mom and have a sister, then have intercourse with her and her child will become your grandson/granddaughter and it will be your sisters kids so your also a uncle grandpa
Let me tell you the story of how I became Uncle Grandpa
by I hrhejejdb June 4, 2019
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uncle grandpa is from a tv show with the same name. Basically he came to be because your grandma adopted her husband. Therefore, he is you uncle and grandpa.
My grandma got sent to jail because of uncle grandpa.
by I lost my boot June 19, 2018
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Uncle by blood, grandpa because he stepped up, in substitute of biological grandpa.
My daughter loves spending time with her uncle-grandpa .
by Miss. Hollywood March 27, 2018
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person: “good morning!”

other person: “wow, he must be an uncle grandpa.”
by kanyesbutthole October 15, 2019
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When your uncle gets married to yo grandma and is now your uncle grandpa.
yo who the fuck is that?

that’s my uncle grandpa you thot
by suckmymiddletoe November 7, 2018
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That grandpa you have that lives by himself in that bigass house. He's loaded. He's got that big shiny SUV. Always got his prescription sunglasses on. Wears a hat even while inside. Socks and sandals all day bitch. Unless he has his fly hi-top blue sneakers or boots. Goes to the bank to get you your fat weekly allowance. In his pajamas. Makes everybody call him Uncle *insert name* You could totally see him in a rap video.
Jake: Howie your grandpa is so cool.

Howie: That's Uncle Grandpa to you.
by McFly got some new kicks March 11, 2013
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An inappropriate Cartoon Network show about the child of a man who screws with his niece: so their child’s paternal uncle and maternal grandfather are the same person.
Uncle Grandpa? Yuck! Who’s promoting this kind of incest to little kids??
by xp649 July 6, 2020
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