I'm not 100% sure on this technique...ok butt in air, legs spread comfy wide and than here is the part where i'm confused on. which way is my thumb supposed to be? Nail pointing down towards the mattress or up towards the ceiling? From what i'm reading I think my thumb nail is supposed to be pointing down towards the mattress. Also what's it feel like with my thumb? A ball? a muscle knot? Don't have a vagina with me to test it out on but will in a few weeks when my g/f gets back tee heheh.

thanks for any help