My dungeon outing last weekend had a bunch of safe wording.
The first was during my first attempt at being a pinata. I suspended myself and my Lady spank me. The basic parameters were that I was in charge of the rope, she would go easy on the hits, and I was going easy in the ties. I had labbed out the ties the night before, and everything went well until I was ready for the spanks, when we noticed my arms were right where she needed to be. They weren't tied at all, so I could move them for a bit, but that messed up the weight distribution, so my nice and easy tie turned out to be quite strenuous.
After that (and a bit of a break), we tried a normal impact scene; until my Lady safe worded because I started to bleed.
After that (and another break with some antibiotic ointment), I tried my hand at another self suspension which lasted until I tried going up, and heard a horrifying creeking sound coming from the rig. Looking into it, it seemed fine; but I was freaked enough to call the suspension off.