The combination of the nutsack, taint and butthole. Can be hit when kicking someone from behind.

Pronounced buttsack.

The U is silent.
"Open the door and kick him right in the buttsaqu and then steal his money and then steal his bitches and then we are tight butthole" -Bruce
by Buttsack Lover October 21, 2011
Get the Buttsaqu mug.