My slave (bedroom only) has asked me to give her a truly grueling experience. We've been in a master/slave relationship for two years and have a very good feel for each other, although we are both the first partners we've shared this lifestyle with, so still very new.
I need advice, because while I have some sadistic traits, she is a true masochist. Our last session involved two hours of tight bondage with flogging and paddling. Short durations of paper binder clamps on nipples and clit (with careful monitoring of blood flow). Longer periods with more traditional clover clamps and clothespins. Intense use of a Hitachi to bring multiple orgasms, and nipple suction pumps. The session left bruises and welts. She was in tears most of the time but confirmed she loved every moment of it.
She has asked me to do a 4 hour test with her at an even greater intensity. These are her only limits: no cuts or burns. No bruises below the elbows or knees or above the shoulders (for social and work reasons). No scat or piss.
She's interested in icy hot, hot wax, breathplay and nipple/clit binding (her breasts are too small to bind). As well as the more psychological aspects such as sensory deprivation and humiliation.
I'm seeking advice on these activities as well as suggestions for things we haven't thought of. Particularly as it pertains to safety. I've read many articles that suggest breath play is impossible to do safely, and so I hesitate to incorporate that into our session, although she wants to try.
Thanks in advance!