Plan is that, for the next 24h you'll be completely at the mercy of his whims. Bear in mind that you need a high rel to even get him to say "okay" to doing this Vahn thing for you.
Much as he might feel sympathy for Vahn, he's not about to go whoring himself to grant the guy the illusion of a good night. Especially because it's gonna fade. The only reason he's doing it, is because you want him to. Technically you could order him to do so, but that would destroy your relationship with Terry. At least a -50 hit to rel.
Granted you get through this on friendly terms, Terry will have you be his for 24h. Meaning that your roles of pet and master will be switched.
You'll have to take him on a date, get him a very expensive dinner, buy a few gifts (some clothing, some toys maybe, plus other stuff he might want). Giving him a full body massage is to be expected, including foot rub naturally, he might tease you sexually, might make you give him a bath, blow him or lick him off, who knows. And to end things he'll get you to have sex with him, naturally.
Something along the lines of that.
EDIT: Oh, and a good sex level nets you some rel point.