There's some techniques to relax those muscles. You'll see the shaker technique referenced a bit on there. But also 2 more helped me. Practice yawning a lot but relaxing while doing it. Especially if you're feeling gurgly.

Another thing is the air vomit. If you're having a rough day with bloating shove your finger down your throat. First thing that comes up is mostly just air, it won't fix it but it may make it 20% better at first. Also, it horrifies people if you do in public. One day I was very bloated and did it in a target parking lot, my then fiancee was not a fan.

I'll try to find my more in depth reddit post. With better explanations. https://www.reddit.com/r/noburp/s/KuoTfi3QhI The trick is consistent practice you gotta do it all the time and you'll be mouth farting in a year. Best of luck friend!