Breath in with diaphram, breath out nearly %70 and wait with an open mouth without doing anything.The remaining %30 air will be pumped out slowly by itself. The more you do it without stuttering, the faster your exhale rate will return to normal. If you go on severe blocks, it will have no effect. That's why people find no solution. Even after therapy, they go on stuttering. Exhale rate can never return to normal in this case.