From a DM from the karaoke co-head:
Quotegenerally we don't really screen for lyrics, fan songs are always allowed, when people are courteous enough to ask i usually tell them to do racier songs after 9-10 p.m. when the vibe is a bit more receptive, but it would also be fine during the acousikaraoke contest block. ultimately use your best judgement.
also like maybe look at the event description for dumpsterfire and see if you think you might have an act that fits that show. (the sign up forms will be up soon)
https://www.fanime.com/events/karaoke/
open mic is first come first serve and you must wait until after you sing your song to sign up again