The act of putting a dick and ballsack in your mouth at the same time. Also called by those who experience it to be a "Super Blowjob". Once known only to be mythical, ballsdick has been video taped, seen it dude.
Also a phrase to use when something really sucks balls. But also can described as sucking dick. Hence ballsdick
Dave: "That report is going to suck dick."
Jim: "That shit is gonna suck balls man."
Jane:"That motherfucker sucks ballsdick!"
Bob:"How was your weekend?"
Walter:"It was sweet man, I got this hooker who went ballsdick on me bro."