No touching each other at all. Mostly, whoever wants to cum next gets onto the bed where everyone has a good view of her or him, and describes their favourite fantasies (I recommend Nancy Friday's "My Secret Garden"!) while playing and showing everything they've got, watching the others playing and watching too, and maybe requesting someone to show something in particular, especially just before cumming. Everyone who cums receives praise, approval and maybe even applause. A quick cuddle afterwards is allowed as an exception to the "no touching" rule if desired, then it's the next one's turn... Maybe right at the end, when everyone knows all about each other's wanking technique and timing, everyone could cum at once, although that might be difficult and nobody should feel left out.
How I imagined it going further after I left was that the women mostly took the lead. Everyone took their time getting undressed and showing more step by step, joking a bit like "I'll show you mine if you show me yours". all relaxed and having fun, until the men are getting hard and the women are getting wet, all playing gently with themselves and complimenting each other, also talking about what they like seeing and doing. Everyone is free to cum at any time, but the men try to hold back until every woman has cum at least once. However, it goes on for hours and each of the men also cums at least twice.
Now I'm tingling from fingers to toes so I'm going to watch a video and play "The Lone Wanker"!