Have him give you a rimjob...

Something in your mind tells you that "rimjobs" are nice, and that they include a person licking someone elses asshole. Since William seems to be in a rather "pliable" state you´re sure he won´t protest.

"I´m gonna bend over, and you´re gonna lick my asshole. And you´re gonna love it!" You then bend over and sure enough he spreads your asscheeks and starts to lick your asshole. He starts by twisling it around your pcukered hole, then tentatively prodding it. He wan´ts to stick it in, but he lacks passion. So you grab his hair and pull him in more, making it clear that you want more.

For extra ****, you flip him down on the ground and then straddle his face, planting your asshole on his mouth. He pushes his tongue into your asshole, and you enjoy the new sensations. You see his erect cock standing proudly, it looks tasty...