I think you've already answered your own question. How about starting with offering tie and tease?
Sessions would be quite vanilla, and you'd still be offering the usual hand relief, oral or sex happy ending, just adapted to a guy whose hands are tied to the bed. You can stimulate nipples, with your hands, teeth or tongue, or invest in your business a bit by buying a pair of nipple clamps. If you don't fancy going into a shop, just order online. You can tease a lot with your body/boobs, hair etc., and start to introduce a bit of verbal teasing, telling the guy what you're about to do to him. For example, tell him you're going to ride him "cowgirl style", until, blah, blah.....   Not much acting involved, just build excitement a bit more than you usually would, bearing in mind you have to be a bit less passive than you would be with a client who thinks he is "seducing" you. It's a lot of fun, and you have a bit more control over a booking, and you don't get pawed and poked quite so much. You can do a bit of anal play (get a box of hospital examination gloves, and make sure you always have enough lube), and maybe buy a slim vibrator that fits up bums.