Well I was thinking of offering two types of courses.
One for people who want to add a good massage technique to their general services. As most people wanting this will probably just be doing it occasionally and therefore using a normal bed, I would hold a 2 to 3 hour session in a hotel room for 2 to 4 people. It would cover things like choosing oils or lotions, how to reduce the stress and strains on your body when massaging on a bed, how to make him comfortable, which areas you shouldn't apply pressure to, different massage techniques, how to use different levels of pressure to bring pleasure, how to make a hand job more than a quick yank, and stuff like that. Even if you end up only rarely giving a massage you should be able to incorporate some of the techniques into your usual bookings.
I'm considering holding this course in London and Southampton (the nearest city to me) and maybe further afield if there is enough interest. I'm thinking around £200 per person.
The other course would be for people who want to make sensual massage their main career. That would be a 2 day course covering everything from the basics to more advanced elements and would be restricted to 2 people at a time. It would be held at my place.