A Boo Penis is the terminology for a penis that has a blue pigmentation. Can also be used as an insult for a wonky shaped penis.
Ex 1: I didn't know Megaminds schlong was also blue, who would've knew?
Ex 2: Shut up Joel, you have a Boo Penis and we all know it
A boo penis is a penis that is blue, presumably a fictional characters shclong
Ex: I didnt know Megamind had a Boo Penis until I saw his ONLYFANS