sack sitter

1. Prostitute/Person who has a lot of sex

2. Person who tries to impress his/her boss. (suck-up)

Example 1 : "Don't distract Jake from accounting, he's trying to awe our Regional Manager."

"WHAT A SACK SITTER"

Example 2: "YOU SLEPT WITH THE WHOLE TEAM?! YOU'RE SUCH A SACK SITTER!"