I just got back from my first formal BDSM play party. It was a great experience.
What got me was that everyone was smiling. Not always in mid-scene, but sometimes even then, and certainly every other time. It was a wonderfully friendly, fun atmosphere. I'd come in expecting things to be a little seedy or furtive, but it was more welcoming than most clothes-on parties I've been to. Just about everybody there was happy. Least I was.
Oh, and an incredibly cute and musclebound young military type grabbed me by my hair, had me struggle and then wrestled me down, and beat the hell out of my tits. I have the most amazing bruises.
I've got to do this again.