If anyone feels like trying, here is a new(?) and untried RC.
Try to breathe in like you do when you are holding your breath. If it’s a dream you’ll breathe in like normal. If it’s RL then you’ll feel suction in your lungs. I hope I explained it well.
Advantage of this is you can try it when you wake easily. Blocking my nose is my most successful RC but when I wake I don’t want to move my hands. With this new RC I don’t need to move. It also means no-one will see you doing RC’s if that worries you (Doesn’t concern me in the slightest )
Let me know if you have any success (Or if this has been mentioned before and my poor search skills have let me down again).
Good idea, I now keep practising it together with nose-pinching and double-reading. It now becomes my main one.
It can have an important side effect: when you move in your sleep and it becomes more difficult to breathe (for example, when you dip your face into the pillow), this might prompt you to do a reality check.
Umm, I’m not exactly sure what happens. You can block your nose at the back of your throat somehow. I think it’s by using the back of your tounge. Like when you suck in or blow balloons up no air goes in or out your nose. So just do that with your month closed and try and suck in with your lungs.
I still haven’t had a chance to try it out in a dream If anyone else does let me know please .
I’ve finally had a chance to test it out myself. And guess what? … It doesn’t work for me either. And I wanted this RC to work too . Oh well, too good to be true. If you still want to try this RC. Make sure you always do it with one you know works.
Hmm… it might be interesting to investigate this further. Why doesn’t it work? Apperantly you block your throat then IRL too? I hope more people can test this.
No, you hold your breath and then try to breathe. You feel the block and suction in your lungs when you try that IRL, and you aren’t able to breathe in.
The theory was that in a dream you should be able to breathe while doing that, but both me and Inch have found out that it blocks you from breathing in a dream as well, even though the nose RC works then (you can breathe while holding your nose).
I tried it this night and guess what? It did not work for me. I had the same feeling of suction in my lungs as IRL. I suppose the reason why it does not work is because breathing through your nose is an automatic action and hence it is performed in a usual way automatically by your unconscious mind in a LD. Breathing through your mouth is not automatic. IRL, you perform this action when you drink or try to breathe through your mouth. This action is fully controlled by your conscious mind as it is not a habit. Therefore the mind adequately responds to the situation rather than recalling the habitual sensation of the air flow as in case of nose breathing.
It would be really interesting to research this in a sleep lab. If you really hold your breath IRL at that moment too - it could be used as a way of communication from the dreamer to the ones in the waking world. Like LaBerge did with the eyemovements.
I think the nose RC works because here you use your dream hand to block your nose while IRL it is not blocked (since in SP you cannot move hands). With the mouth RC you block the way by closing it off internally, and you can do this even in SP!..
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If I hold my breath, I can’t breath in… And if I breath in… then I’m not holding my breath 
If anyone else does let me know please 
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. Oh well, too good to be true. If you still want to try this RC. Make sure you always do it with one you know works.