The only thing I'm worried about here is the poential risk of fracturing/otherwise breaking the pubic bone. That would really hurt and make sex painful and awkward for a long time afterward. I think as long as the kick is done with moderate for and comes from underneath or behind, there shouldn't be a problem, but it's worth considering.

I don't do it often, but when I do, my preferred way to do it is when my pet's on all fours and I can do it from behind her. I find that gives me the best angle and control of my kick. Just food for thought.