SanJapan after hour parties?

Unfortunately the main Facebook group/discord doesn't allow discussion for after hour events.

One of the things I read about SanJapan is that between the 2 hotel blocks, 1 is considered the party hotel.

My question is, as someone who is going for the first time all by themselves, what are these "parties" like?

Just friends hanging out in eachothers rooms? People meeting at the con and going back to a hotel room to party? Hallway ragers? Or are there really no parties?