3. Is it physically dangerous? That depends on what you’re doing. In the Finnish study, bondage and flagellation were standard: More than 80 percent of the sample had done them in the preceding 12 months. The riskier stuff was far less common: piercing (done by 21 percent of the sample), skin branding (17 percent), hypoxyphilia (suffocation games, also known as breath play—17 percent), electric shocks (15 percent), and knives or razor blades (13 percent). The California study found a similar pattern: Bondage, flogging, and spanking were standard (more than 80 percent had done them), but other practices—“fire play” (20 percent), “piercing play” (20), cutting (14), branding (9), and scarification (5)—were rarer. Some potentially dangerous activities were surprisingly common—“electric play” (42 percent), “knife scenes” (40), and “breath play” (27)—though in many cases, the implements were probably just props. It looks as though about 20 percent of these folks are actually cutting, burning, zapping, or partially suffocating each other.