You try to breathe through your nose in waking life - obviously you can't, but that's not the only thing the RC does - it also causes pressure in your sinuses. I've done numerous nose-plug RCs in dreams and besides being able to breathe, I also don't feel any pressure (unlike in reality). This has become another RC almost in itself.

Anyone else consider pressure when performing the RC?

If not, that's something else to think about when you're doing it!