I realize that these questions were not directed at me, so I will be brief.
I'd prefer to answer those all at once. I don't know about perfectly still and motionless, but it's reasonable to assume that she was under control. As for how, I think it's helpful to remember that
1) little children don't always know it's wrong, especially if their victimizer is a loved one. Children are very easy to manipulate. That's why they make such good victims.
2) It's actually fairly common for digital penetration, even repeated, to not do much damage if it's done carefully enough.
3) As much as I hate (and I DO mean hate) to mention this, there is the possibility that JB might have begun to associate this attention with love and actually get to like it. Before anyone jumps on me for this, let me mention that I have read accounts of females who were molested as children by their fathers and claimed that they did like it after a while. One of the posters here--I can't remember who--claimed to have uncovered the abuse of one of her students (kindergarten, I think) and that child did in fact profess to like it.
There isn't enough soap in the world to get me clean again.