Blunders

Describe the biggest faux-pas you have ever made at a play party or during a BDSM scene.

During needle play with my partner, we went over our normal limit of needles. She was standing up in the bathroom, I ran my fingers down the needles on her back, about 30 needles. She fainted, falling into the bathtub, creating more needle damage. I had to figure out how to pick up this dead weight porcupine without causing more damage to her or myself.
"Letting my pussy run free" In the middle of a very serious afternoon of discipline and bondage, I was taking a breather and a sip of water. My boy lay duct taped and prone on the floor. At that moment, my cat, who could usually be relied upon to be discreetly under my bed, sprung into the room in a fit of curiosity and was immediately drawn to greet my my visitor by head-butting into the back of his testes. The severe edge that I had worked hard to maintain immediately disintegrated into hysterical cackling and a less than graceful effort to remove the cat.
Speaking to another Master without asking permission; boy was I in trouble but I liked it.
Asking the Dom if "that's the best he can do".
Going out for a smoke in the middle of a scene with chain still tied to my back.
I didn't use my safeword when I should have. Thankfully the Dom was observant.
... dropping a candle on his penis...
... having a candle dropped on my penis...
Touching a submissive without the Dom's permission.
In a heavy flogging scene I almost took the head of a spectator off with my back swing.
Touching people's toys during a scene.
Going to a clothing optional dress-up party and being the only one who took the "option".
Calling my Mistress a sadistic bitch whilst I was still trussed up.
Allowing myself to be clipped to someone other than my Master and being punished for it. Oops, that was a good thing!