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3.
The skin that connects the penis to the scrotum.

The "&" in Cock & Balls
Yeah baby, pinch my tweenis.
by Squeeky Clean Sanchez August 22, 2008
 
1.
n.see gooch. fleshy area between the scrotum and the rectum. Between the penis and the anus thus tweenis. That part you might hit if you fall riding a guys bicycle.
"My friend Kris fell straddling the back of a chair and luckily missed his balls but totally bruised his tweenis."
by Anonymous March 27, 2003
 
2.
genitalia that is sizeably much larger than an "average-sized clitoris", and yet still smaller than an "average-sized" penis. it's somewhere in-between.

individuals labeled female at birth, and who have been on or are currently taking testosterone, often-times have such genitalia.

the longer word for such genitalia could be "clitweenis", but we'll just call it 'tweenis for short.
once i started taking testosterone, my clit definitely increased quite noticeably in size. now it's a 'tweenis!!!
by earthcrunch July 10, 2011
 
4.
a tweenis is part male and female preferably a male cat because it doesnt have penis that hangs out but it doesnt have a vagina either so its called a tweenis half twat and half penis
paws the cat has a tweenis.
people born with both sex parts usually have a tweenis
by Chrissy1987 December 13, 2008
 
5.
Portmanteau word, made up of "tiny", "weiner", and "penis". It's an insult similar to calling someone a "dick".
Stop being such a tweenis, dude!
by Goatrider March 16, 2006