Ducksen is a word of insult for a way to say something mean to somebody in such a situation like school; without getting in trouble because most teachers or adminstrators don't know what it means.
Ducksen means:
D-Dumb
U-Ugly
C-cock-sucking
K-Kinky
S-Selfish
E-eww
N-Nobody
It seems immature; but its one of the ways to insult and get away with it.