sack mapping 

shining a flash light through a stretched out ball sack and having a friend trace the vains and other "landmarks" out on a piece of paper, then use a point on the map to decifer where you want to go for the night by comparing it to your local city map.

1."Lets do some sack mapping tonight to find out where we should kick it tonight."

2. Friend: "dude I dont know where to go tonight."

You: "me either, lets sack map it."

sack mapping by the dick fart September 23, 2011

sacktapping 

touching one's genitals. can be used in various circumstances, e.g. sacktapper, sackmacker, sackslapper, et cetera. often used to insult one or to denote someone as a good friend.

didn't you, you sackTAPPER?

sacktapping by Ryan September 22, 2003