Lite BDSM, a little biting and some hair pulling is fine by me. I've had girls ask for some really rough stuff and I've done it for them, but not really what I'm into. I've got nipple clips, rope, leg spreaders and a leather paddle for when the time is right.
One girl was really into "rape" and wanted me to force anal on her (without lube) and even though I love anal, I didn't enjoy holding her down, spanking her ass as hard as I could (red welts) and jamming my hard penis inside her as she screamed. She also wanted to call me daddy while I did that, but I drew the line at that. I couldn't handle her calling me daddy. I had a ball gag to take care of that request.
(By the way, what is with girls wanting to call me "daddy"?)