I think this is pretty normal especially since you said you can do it 10% of the time. The other times you can't you are probably nervous about being able to yawn which makes you not be able to yawn cause you are thinking about it too much. Kind of like when you really want to go to sleep early and are worried about getting too sleep so it makes you have trouble sleeping.
I can't yawn!
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I think this is pretty normal especially since you said you can do it 10% of the time. The other times you can't you are probably nervous about being able to yawn which makes you not be able to yawn cause you are thinking about it too much. Kind of like when you really want to go to sleep early and are worried about getting too sleep so it makes you have trouble sleeping.