How do I read this room

So my Dom (53m) and I Sub (49f) were playing on a bed in a club. We had three other couples come into the room and start playing on the bed with us. At one point a girl was resting on his leg. At some point the bed was full and the door was closed. My Dom and I had no idea what the etiquette is for that situation. Do we play with the other couples? How is that approached? They were mid stroke. I cannot imagine being like…. “Hey how are ya? Wanna swap? What are your limits?” That brings up another question. We are more bdsm than swingers. How do we broach this topic with others at clubs. It’s always very obvious that we are into bdsm since I am always leashed and collared.