the equivalent of callin someone an ass or a retard
"yeah, i couldnt go, my parents were being dankwagons"
"damn, is that guy a dankwagon or what?"
an insult or mockery to a person who is being stupid, retarded, annoying, or just "gay".
"Dude, don't be such a dankwagon" or "man.. is he a dankwagon or what?"