This word is a combination of 86 and 69. Used when referring to having sex with a person then kicking them out or leaving immediately afterwards. Similar to a booty call or a one night stand.
If you see a male or female you would like to have sex with and thats it, you would say "I'd like to 89 her/him" or "I 89'ed her/him last night". This word was created by a buddy and I at the bar when a very drunk girl said we should 89 a guy for being rowdy. She mixed up the words 86 and 69; thus, the word 89 was born. We found it amusing and have not herd the term used anywhere else, making this a great place for it.