I’ll try this out next time but I can assure you that I have a lack of air. One of my worst stutters are ‘who, what, where, when, why, how’ and I can’t latch onto the end of the words. It just ends up as a breathy ‘whhhhhhhh’ until my lungs start hurting lol. Ive never heard of valsalva maneuver before. I’ll have a look