The more offensive version of douchebag. Douchebags are relatively good things (keep those cunts clean), so, naturally, shower sacs would be horrible things.
Sarah: You're such a douchebag!
Val: Thanks, but you come off as a shower sac.
Sarah: Ugh! Fuckmuppet!
A huge tool. Who gets bossed around by little sophmore hoes. Sprute Sacs usually get red in the face whenever they face adversity, or are at the butt end of a joke.
Dude, quit being such a Sprute Sac.. No one likes you or that sophmore hoe that owns you.