i think it’s clear it’s an actual drawing class, led by a tutor but with a combination of the thrill that comes with having a naked man (otherwise we would be drawing fruit bowls).
And model (wink wink), sorry I don’t get you what does that mean?
I mean if it's a cover and the lines between model/stripper/other services offered are blurred. A bit like when men go to see somebody advertised as a 'masseuse' - sometimes they are going for a genuine, professional therapeutic massage, but very often, it's a cover for something much more seedy.
I'm not suggesting that this is necessarily anything as full-on as that at all, but you said it yourself that you/the booker is after a thrill. As I understand it, a genuine artist would be interested in capturing the features of the human body, rather than 'looking for a thrill' - and would be just as likely to be very interested in artistically capturing the bowl of fruit the following week.
It's just that, at one end of the spectrum, you would have a serious art class and at the other end it could be scene-setting for full-on 'adult' services. If, as it sounds, you aren't especially near the former end of the spectrum, I'd probably want to make sure in advance that it's nowhere near the latter end of the spectrum, unless that's what everybody's wanting/expecting, I suppose.