sack slide

1. An act within oral sex when the scrotum (sack) is licked continually up and down motion (sliding)

2. The act of travelling down an amusement slide on a sack

1. "I can make a guy ejaculate with a sack slide better than anyone else"

2. "Hey man, what are you up to tonight?"
"Heading over to Luna Park for the fun of a sack slide."