A Jeanis is when a girl is wearing a pair of jeans, which consequently make it appear that she has a Penis. If you are a girl, and especially if you grew up in the 90's, then you have probably had at least one Jeanis in your life.
by MitchShevae June 30, 2010
(1)the Jeanis is something that takes shape in the front of your jeans that makes it look like you have a penis in your jeans, even if you don't (for the girls) (2) if you actually have a penis and the tiny Jeanis that occurs, makes it look bigger.
by jamie laurence April 24, 2011