I saw a YouTube on this very thing this week (dr Ken berry) and tried it. I must have done nearly 100 and saw no change in bgl. He claimed it worked almost instantly. I gave up testing after about 15 mins. Maybe I didn’t wait long enough, do it right etc but didn’t seem to work for me. Interested to see what others think and if it’s worth another go or not
eta: having skimmed very quickly through the study I didn’t do it long enough nor test long enough. I either didn’t pay attention to the video I saw or it wasn’t clear the paper used 2 and 3 hrs of contractions not 10 mins and the instant result took at least 30 mins.
edit to get the right YouTube reference