It's probably best to start with an enema!

This was James' world now, and there was no way he was going to use a condom! Plus, he'd always been a bit turned on by medical roleplay and enemas.
So he left the other equipment on the front seat of his car, and approached the other man with the portable kit he'd summoned. The tip of the nozzle was already lubed, so he pressed it against the other man's asshole and watched as it was sucked in. Then he flicked the tap and saw the liquid begin to stream down towards the, now hidden, nozzle.