A cross between a dick, cock, and penis. When you don't know which to say to a girl, you combine them all. Dockis is the true scientific name for a dick, cock or penis. They are usually 1 - 24 inches in length, and come in many colors.
Boy: Hey would you wanna suck my dockis after school sometime?
Girl: I love sucking dockises, of course!
Boy: Sweet, my dockis is getting sorta hard.
Girl: Stop, or I'm going to punch you in your dockis.