Using an anesthetic agent to create a numbing sensation over the users penis to still allow erection, but dismiss any feeling in the area. This allows the user to masturbate his penis without any feeling creating a sensation that the user is jacking off another person.
Thomas is not openly gay, therefore he must use the reverse stranger in order to feel like he still with another man, and get the pleasure he wants at the same time.
When you lay on your cock until it falls asleep so it feels like you're jerking off a stranger. As opposed to a Stranger, where you sit on your hand until it falls asleep, then masturbate for the sensation of being jerked off by a stranger.
Having tired of the Standard Stranger, Charley decided to flip onto his belly and go for the Reverse Stranger.