"sub-space" is a trance state, where the sub looses herself, and might have any number of effects. there are differing levels that people go into space, depending of circumstance.

with lisa, I find that if i start off with service type situations, giving her lots of commands, having her fetch things, and then proceede into impact play, i can have her almost out of her body, and unable to move. sometimes she cries, sometime she wants nothing more than to grovel at my feet, sometimes it makes her beg to be fucked. again, i think that depends on her mindset going in, and hte amount of intellectual play i mix into the pain play.

pure pain ellicits more of an out of body sensation
intellectual play more tears, i think

and a bare handed spanking will send her into a fuck-me frenzy