I took me 6 weeks to get it to pop, specifically trying to get that, with cheats enabled. Then me and friend got assaulted. I as playing an abstinent guy. Maybe abstinence makes it more difficult?
Side note: Dancing doesn't seem to be a skill you can learn, is everybody constantly terrible at the dancing at the party?
At present, the only reliable (though not very) means I have found to improve your Dancing skill is to have a computer & a Livestreaming account & put on Dancing streams. When Dancing became something you could do at the Friday night parties, I was very happy, until I also noticed that even successful Dancing tests there don't seem to advance your Dancing skill. I hope that is just a bug that will get fixed eventually.