Does lying on your back restrict the Aneros's movement?

@Spanishguy69 , there's no reason why flat on your back should restrict the Anero's movement, but legs straight might, if kept togehter, since the inside of your legs could restrict the movement of the parts of the Aneros that are outside of your sphincter. If so, it can be solved in a variety of ways such as spreading your legs, holding your buttocks apart with your hands, raising your knees, elevating your legs or whatever suits you.

I cut off the curly part from all aneros models I own. This frees up the aneros to move freely even with legs straight out front when lying on my back.

Im usually lying on my back with my legs bent. You coul try using a pillow or a folded towel under your lower back to elevate your hips

lying on my back is currently my most favorite position,but i done it with the handle cut off. else, the mattress and my butt will just interfere its movement
while lying on my back, i could add some variety to my legs position such as bending them, lifting and placing it on the wall or just holding my butt apart will make the aneros hit my prostate with diff pressure which is very enjoyable. the only thing that does not work for me is to have my legs straighten out

@Spanishguy69 lying on your back does not impede your massager's movements. Use the position you are the most comfortable with. I think time and more session time will help you maneuver your massager. I also suggest doing daily Kegel exercises to help straighten your PC muscles. Good luck and enjoy your sessions.