It's an odd premise but I've seen this kind of story before and it can be done well.
Playing the demo was fun albeit a bit short, but it was amusing and I appreciated the mc was not a hyper-horny fool, he was not blind to how attractive the first client was, but also under pressure and not a super confident sex god who did his fist "job" to perfection on the first try.
This is fun and I would like to see more, as long as the character interactions remain interesting and things get nicely more complex over time.