Another term for a nice, round butt. Can also be a butt with nice proportions; usually referring to women in spandex. But, can also refer to men with fairly plump, perky buttcheeks.
Brandon: Hey man, look at Dave's doopadoop! He must be squattin more.
Shawn: I know. I wish my doopadoop was that perky and plump.
When a doop is being a poop. Rather gay, also can be a "doopypoopy" when the doop is watching youtube and the black men are shaking it. (When you see a doopypoopy just yell "doop doop doop!")