I think that the sub that you have helping you should have selfconfidence becauseof the fact that they will usually be watched during a scene and I also think that they should be dependable because of the fact that you do training sessions with the Doms that you mentor. and I also think that they should be some what experienced in the lifestyle because if you want to try something new they might not be so hesitant to do it.... here is an example of what I mean by that let's just say that you were teaching a new Dom the very basics of knife play and you had a sub who is still some what new to the lifestyle helping you out they may hesitate about letting you demonstrate on them so it would be a wasted session due to you not being able to show the Dom what you wanted to show them.