A common nickname given to blonde boys who are given the name Axel.
For the most part, these kids are found in urban areas and have friends who aren't used to the name "Axel," and thus create awkward nicknames.
Thus the nickname "ax-ax".
Joe: "Who is that guy?"
Crisolo: "Oh, that's ax-ax"
Ax-ax: "Hey! What the fuck, guys. I told you to stop calling me that!"
Joe + Crisolo: "Aw...Ax-Ax"
Ax-ax: "Fuck you guys."