Junior high move

[lukealex]

This is something that I have always wondered about, but it has just come back to me.

Back in the day, when messing around I used to jump off someone else's back when they were on all fours to dunk the ball. Then I had no idea if it was legal but now I don't think it is.

What does everythone else think and is there a rule I missed when trying to figure this one out?