I'm a very un-spiritual, atheist, science graduate eg I enjoy yoga for the physical workout and completely zone out almost everything my yoga instructor says while respecting that she and a lot of the rest of the class experience yoga as something spiritual, I enjoy it just as much as them without that. Tantra is like that for me. I did a course in it and studied youtube videos, read about it and found the whole lot to be a bunch of pseudo-mystical mumbo jumbo.
But I still offer it. When clients ask for it, I play some yoga class type music like thievery corporation or whatever, light some candles, throw a sari over the massage table and make a little speech at the beginning that I make up on the spot. something very similar to what Velor said. Then I give them a very slow, sexy massage and a hand job. I've had clients say it was the best tantric massage ever and wasn't it amazing how "in touch with each others spiritual auras we were and blah blah blah."
So it's possible to offer it and do it very well while experiencing it as nothing more than marketing claptrap. If the client is expecting tantra and wants to experience tantra and you give them something that looks like you are too, that's what they'll experience.