A client mentioned to me that he went to a massage practitioner doing Tantra. He said " It certainly wasn't Tantra because the practitioner did not even touch my cock."

To me there is a difference between Tantra and Erotic Tantra.

Tantra practitioners use various method to allow the flow of energy in the full body which may or may not involve genital stimulation.

Erotic Tantra most likely includes genital stimulation.

If you assume that during a "Tantric Massage" that you will receive genital stimulation or any other erotic stimulation.. you maybe wrong.

Always ask for what you want.