Don't interrupt a scene. If you don't like what's happening, leave the area. If you think that what's taking place is unsafe, tell a dungeon master.
Hold your comments until after the scene. The scene does not end as soon as the action is over. Most tops will tend to their bottoms through a cool-down period. This coming-down process is important and shouldn't be interrupted. Novices attempting to start conversations with the top or the bottom during or immediately after scenes is one of the most common errors at play parties
Clean up after yourself. This means more than just move your toys out of the scene area once you're done. At the end of the scene, please pick up any debris around your play station. Also, grab a bottle of disinfectant and use it to wipe down any equipment you've used.
Leave space for the top to move during a scene. If the room is too crowded, stand against the far wall or leave the room. If the top asks you to move, then move! In most play circles, if you get close enough to disturb the scene, the top would be within his rights to swing something at you.
Be quiet while scenes are going on, or go to the social space to chat! The admiring or joking comment you think you are quietly whispering to the person sitting next to you is often heard by the bottom or top, whose senses are sometimes hyper-tuned and on edge.
Do not join in scenes uninvited, even if it looks like they are free-for-alls. A scene that might look to you like lots of folks are joining in to pleasure or otherwise play with the bottom might in fact be carefully orchestrated by the top and other acceptable players to look casual. Or it might be that the top is subtly signaling audience members he knows to be acceptable. Join in only if the top clearly beckons you in. If in doubt, don't join.
At the party, relax, be yourself, be open and friendly; ask questions about BDSM technique if you need to make conversation; listen to what others have to say. Bring your sense of humor.
Do not mention anyone at the party to those not at the party without that person's express permission to name him. These parties are private; what happens there stays there.