There's some science on training those muscles, even without upside down drinking. "Dry swallowing" while on an incline seems to do the trick just fine. https:

There's some science on training those muscles, even without upside down drinking. "Dry swallowing" while on an incline seems to do the trick just fine. https://pmc.ncbi.nlm.nih.gov/articles/PMC9550520/ https://pmc.ncbi.nlm.nih.gov/articles/PMC9550520/