Hey tbug, I think the new foam rings really help with getting the larges to stay on. I tried it without, and they kept farting off, plus it hurt so much after a couple of minutes I went back to my foam rings. I tried the old type foam rings, because my medium rings stretched, they definatly didn't work that great because there more stiff then the new ones. I couldn't get suction with them on. The heat of the water also helps, but I can still get them on without it. I just lay on my back, I had to position them higher on my chest to get suction, and pinch one tube while I got the other one on. Hope that helps! Good luck to you!!