Learned to burp at 26
Found this sub and thought id share on the off chance that this helps a fellow no burper out there. My entire post infant life I was unable to burp. No carbonation ever, constant gas pain, even went to the hospital a couple times in high-school just to learn, yeah that's just gas, heres some nausea meds, you'll be fine. Did my best to manage via diet but there's only so much you can do.
About a year ago I happened to have the tiniest burp, like undetectable by anyone but me tiny, while I was scrunched up on the couch. Was able to replicate it a couple weeks later by sitting in the same position, opening my mouth, and consciously relaxing everything whenever i felt the gurgles; those loud, base of the throat bubles that never come out. Over time with practice I think I have trained my body to let the air out, and can now burp maybe 60% of the time even in an upright position. Its glorious and i still get excited when it works.
The scrunch: sit on couch or floor with your back to the back of the couch or a wall and your knees up, feet close to your butt. Sit slouchy, c curve in the spine, mostly just shoulders touching the back of the couch or wall. think "staring at your phone too long" relaxed slouch. Now lean right onto your elbow, stretching out your left side slightly. Tilt your face up and face the left shoulder slightly and relax the mouth open. I found everything must be relaxed, so adjust as needed for your body: pillow under the elbow, at lower back, under knees. It seems the idea is open up the left side and provide a straight path up from the left.
Sorry if this is an already known thing or unhelpful. Just hoping this works for someone out there and can provide relief. Good luck everyone!