Back-nine 

When you get little sleep at a friend's house/wherever you passed out, head home, and get the rest of the sleep you need to get a full night's rest; a non-contingent nine hours of sleep.

John: Wow, three hours of sleep at this party? I had better head home to get the back-nine.

Back-nine by kingPontus January 25, 2010

back nine 

Reference to the anus in regards to the performance of Anal Sex.

1. I played the back nine with my girlfriend last night.
2. I teed off on the back nine but she kicked me off the course.

back nine by Wes Wylerson May 2, 2006

Back Nine 

The backside of a female.

Bro, did you see the that girl that just went by.

Hell yes, that lady had a fine back nine.

Back Nine by sanfred January 20, 2011

Back nine 

Lost my place in line for following the rules and being polite. back nine

“I just lost my place in line for being polite “ back nine

Back nine by Stupidwords4people June 4, 2018

Back Nine 

The act of having anal sex while on a golf course.

Hey baby, lets go to the golf course and do the Back Nine.

Back Nine by Golf-Pro641128 February 17, 2010

Back nine 

Being polite in a crowd

Fucked up the ass back nine

Back nine by Stupidwords4people June 4, 2018

Back nine 

Getting raped up the ass, non literally, maybe literally.

*Killionaire* Wow, you motherfuckers got raped up the back nine!

Back nine by T-painizzle May 11, 2009