Ok, here goes. With my girl, we'd like to try more positions with me behind her. Namely, standing doggy. However she is short. 5' 3" and I'm not that tall, 5' 10", but its uncomfortable for her the time we tried. Bumping the cervix, to be specific. So i need suggestions on how to make this work better. Heels or something to stand on, and how high. Does she need to be at my height or taller? Back angle? More upright and arched? I'm about 6 1/2". Help us out please. Aditionally, will reverse cowgirl be kind to her cervix? Thanks in advance.