It isn't really that hard. Think of it as you describe something, a scene or scenario and then your first action. I then describe my reaction or actions.
So the one that stands out in my mind is a hanging scenario (which I am not really into) where the guy described how he put the rope around my neck (and it was a single knot rope so I would choke to death not break my neck) and tightened it up. The words he said to me, mocking me humiliating me, commenting on my body (I was of course being hung naked). I begged for my life, pleaded offered him whatever he wanted and then he pulled on the rope and as I "rose" up into the air I made strangling sounds and described how my body swayed and spun as I kicked and struggled fighting for breath. i keep that up for about 3-4 minutes, describing the scene, my actions, my face turning red and then purple as I slowly choked to death and then I "died".
I'm sure he was getting off to the whole scene as he created it in his head based on my description. I must have been good because he wanted to set up a regular session.
Now you have all of the above in SL through instant messaging (or even sounds I can play like begging for my life or strangling) plus the computer simulation of seeing "me" say dance on the cross and eventually die. With the right stuff you can whip me and I can make whip marks appear on my body.
Of course it is an avatar but even that is great. In real life I am a brunette so my avatar is a brunette but this guy I was playing with wanted to do a redhead so I switched hair colors and he was torturing and raping a redhead hanging from an "A" frame.
kisses
willowfall