Regular Washington city slang for somebody who's extremely lazy and not willing to contribute to any social activities.
You aint tellin' me that my neighbour is comin' too? Which mottafukka ordered this sucksack to join my party? Fuck him, he aint comin' in; this geek's a weirdo!
The action of your sack (Male Genitalia) getting orally sucked, testicular involvement only.
I just sucksacked the band director, I got a mouth load of cum!