An informal promise made from one person to another to gaurantee them the privleges of having anal sex in the near future.
Guy 1: Hey man you will never believe it! I put in for my anal passport with Melena yesterday. I'm totally going to put it in her butt next time I see her.
Guy 2: Thats awsome dude, I got mine a few months ago from Jessica. It pays to ask early man. I'm gonna tag that ass next weekend