Exploitation as a consensual joke? I have to think about that very carefully.

Yes, that's a very clear way of summing up my discomfort. It's very subtle, and therefore hard to pin down or object to. I don't have any difficulties with people wanting to have sex with each other, or be voyeuristic - as long as it's fully consensual pretty much anything is fine by me. The question here is really about consent, and what is consented to implicitly, and what is not.