It sounds to me he knows you are shy and he is almost doing it as a power thing,I bet he wouldn't say anything to an older more assertive therapist.What do you do on him ? if its massage then give him the worst massage he has ever had,if you know he likes certain things don't do them.Dig your thumbs into his archiles tendons do lots of hacking don't do anything soothing and also don't strike up any conversation with him at all,if you do have to speak to him keep it blunt,yes or no and nothing Inbetween dont
make any eye contact with him in fact put eye pads on him,I'm sure he will get the message.
I think you need to get a bit angry about the way he is making you feel.