Any kind of sex tend to give lots of exp, which is why people suggest chain masturbation as an early levelling strat and rape loops. I've personally found prostitution to be very, very effective if you're succubus specced, and if you go hard into maximising sexy through gold piercings and dancers outfit then prostitution in the golden club can be shockingly profitable, 5-10 small copper per V/A/Full service, less for blowjob and handjob but they also consume less stamina. You can earn so much that it becomes cost effective to buy out boss mama's stock of good soup to prostitute more, and you can recycle all the cum you get from blowjobs and cleaning privates after filling your holes into white sludge at the cooking pot in the bar to fuel even more sex the next day. Depending on the act you can get as much as 7500exp per customer in less than a minute.
If you're combat capable you can instead repeatedly clear the north tower goblin lair to free prisoners. 5000 exp and 1 moral each plus 6c or 2C if rescuing non-moots.
