[Most Likely NSFW] - How did sex orgies in Ancient Rome differ from contemporary sex orgies? (Aside from the loud music)

My guess is that ancient orgies were more religiously bound – the participants thought they were carrying out some sort of ritual.
Whereas (from what I understand – I haven’t participated in one) current orgies are more carnal and less motivated by the command of the various gods.

Did ancient roman men cavort only with slave women? Or was the orgying done with men and women of the same socio-economic class?