Hmm. I really like succubi, like really like them, though I don't like when they have to be lethal. IMO it's better when they can drain a guy and he'll be exhausted and weak, but he will recover (and come back to offer her more). Of course, they could drain a guy completely, but doing that would usually be a bad idea, killing tons of people attracts attention.
The combat is an OK start, but it is really broken and needs fixing badly. Biggest thing is that if you have the ability to build different characters with different stats, there should be more than one legitimate build yet that doesn't seem to be the case. I tried making a mage build and it really doesn't seem viable, having to recast mesmerise every turn is no good. Make the duration of that scale with intelligence to make that playstyle viable. Maybe have some videos of her making him jerk himself off instead of always doing it herself? Also should reconsider making succubi so weak, a succubus overpowering a guy and pinning him down to ride him would be another way to play it.
Also why on earth does the first handjob/blowjob automatically fail? I can see no reason for this, and there should certainly be ways around it other than mesmerise. Certainly knocking him down with tail whip should also make the guy vulnerable. Plus that should also stop him attacking, the combat is just stupidly slanted in favour of the guy. His attacks always hit and he can often get a second one, while the player's attacks often miss and they don't get this bonus attack.