Yawning in general is still quite a debated topic in science. Its purpose is not fully known.

Yawning is so fascinating. It's often contagious, even between humans and other animals, it's an involuntarily reaction and can happen repeatedly in quick succession like sneezing, and reading and/or thinking about it can trigger it (as has happened to me multiple times while writing this).

I can't directly answer your question, but what I can say is that it must be important as far as evolution is concerned. In addition to all of the above, it negatively impacts multiple important senses simultaneously, and to your point, we can somehow feel whether or not the yawn was sufficiently satisfying.

Maybe the same as a "ruined orgasm"?

I heard about this recently from a different article, but from my understanding, when we yawn, cerebrospinal fluid moves away from our brains. Cerebrospinal fluid “keeps the central nervous system running smoothly, delivering nutrients and removing waste.”

So, as a laymen, I think our brains are flushing the gunk out when we yawn. Having to yawn a second time, to me, would indicate that we didn’t get all the gunk out the first time.

I immediately had to yawn when I finished reading this haha.

It's called air hunger and is a mild form of shortness of breath and I get it constantly. (Edit to add: I know EXACTLY what you mean by the jaw thing and that arbitrary bodily sensation of "u did it wrong tho do it again :( but right this time..." and then it keeps going and going and going until you finally manage to breathe in right somehow.)

• get a medical checkup just to make sure nothing is actually wrong with your lungs, but especially have your iron levels checked
• CUT BACK ON YOUR CAFFEINE AND OTHER STIMULANT USAGE (nicotine is another common stimulant)
• it can also be due to anxiety (which is why you wanna cut the stims) so reduce your lifestyle stressors where possible, seek psychiatric treatment otherwise

Not a doctor but I am an RN (but still not your RN).

I know this feeling. I'm not a doctor and I can't offer a thorough explanation. I am prompted to share my experience though in the hope that you find it helpful.

For a long time I was focused on forcing the yawn or otherwise putting effort into it as you described. What I realized was that the missing ingredient was the depth of my breath. My body is trying to relax, initiated a semi-autonomous routine to do that, and I'm interrupting it.

When I'm too tense I have trouble yawning. If that's happening the only sure way I've found to satisfy the yawn is to drop my shoulders, breathe from my stomach first, and let the yawn take over. Sometimes the jaw still ends up pushing open quite wide. Sometimes not. The key is that I'm not trying to control it either way.

Now it feels as odd to force my own yawn as it does to overthink my own breathing. The only viable solution seems to be giving up on control over it and letting my body go on autopilot instead.

I get this sometimes when I have anxiety. Almost feels like I can't breathe enough, and I have to keep yawning.

Sometimes yawning is triggered by a perceived need to get more air (CO2 build-up in the body). The lungs might sense that CO2 went down after yawning, but then the blood deposits more as the lungs were no longer saturated with CO2, and after that you need to yawn again.

Or it's randomly triggered by some other reaction 🤷

I hate yawning. It often causes a muscle to pull in my jaw area and it takes a few minutes to clear out. Sometimes a day.

I prevent myself from opening my mouth too large.

Thank you. I feel like there is a certain point at which go 'pop' when they are fully filled and it just doesn't feel like a deep breath or full yawn when I didn't feel that

A yawn is the brains wish to not have to even and sometimes you don’t get quite enough on the first dip so you have to not have to even even more

We don't even know why we yawn in the first place.