Prepare him with lube

You squirt some lubricant that Lucy and Josh had left on the bedside table onto Josh's. It dribbles down his crack. As it covers Josh's hole, you press your finger against it, pushing your way inside. Josh gasps, but doesn't pull away. You remove your finger, then plunge it inside again, moving it around as you do.

The next time, you add a second finger, stretching Josh's hole wider than before. Josh moans loudly. You carefully move your fingers apart, stretching Josh even further.

Finally, you pull your fingers out completely. Josh moves backwards, needing more inside him. You happily comply. You cover your cock with lube, then line it up with Josh's hole, and push inside. Josh lets out a yell, and thrusts his body towards you, trying to get as much of you inside him as possible.

Josh's ass is warm and tight, tighter than anything you've fucked before. It's not long before you are on the verge of cumming. You pull out of Josh, and jerk yourself off to completion on his back.