I put a Seacure mouth piece on my PRISM's SDV. Much better that the original mouthpiece that came with it, in the way of jaw fatigue, but during the Pre-Breathe sequence, I tend to start gagging & wretching (never vomited), sometimes quite badly. During the dive the gagging does not seem to be much of a problem, just during the Pre- Breathe. I do have an ultra sensitive gag reflex. I have trimmed the Sea cure just about as much as I can & still have it be functional. My Open Circuit equipment I use a comfort bite (has a bridge that rests behind the teeth of the upper jaw) mouth piece & love it! But it seems not to have the "staying power" (wants to pull out of my mouth) of the Seacure, especially when I turn my head. Any ideas? suggestions? Anyone else have this issue? Thanks!:blinking: