I'd assume the experience is different for ladies than it is for men. With a lady, having chemistry of some kind with both the lady and the guy is beneficial.
As a man, dual chemistry isn't required. I simply have to have chemistry with the lady and not piss the guy off. Which honestly isn't very hard to do. I've had a lot of fun times in this situation in over the years... sometimes guys just want to watch and other times it can be a bit more interactive [no-homo]. If you have ground rules let them be known up front when you're sober and before any play time starts so that your boundaries can be respected... and sometimes bent a little
ATM