The act of engaging, after a solid regimen of vaginal sex, in the act of anal sex; also known as sodomy. One can also hop onto the back nine right away if possible. This phrase is a simile derived from the game of golf when one plays the last nine holes on an 18hole golf course.
Me and my girlfriend were having great sex last night when all of a sudden we tried to switch it up and ended up "playing the back nine" wink* wink*.
A small piece of information. Derived from the word ken, used often in the scottish language and is synonymous with knowledge.
Person 1: "Hey I don't get this shit. How do you solve this problem?"
Person 2: "I got that one. Give me some kenlets on this assignment and I'll help you w/ that one."