My BP sometimes makes noises through her nostrils, but she is completely healthy and does not have RI. Sometimes when I check inside of all of my snakes' mouths, I will usually notice some small bubbles in the throat but those just happen to be saliva bubbles. Though, if the bubbles were big, could be a sign of RI. And if you try to pop it, and the bubble doesn't pop, that's most likely a mucus bubble from having RI. The noises you will hear when a snake has RI is popping or clicking when they breathe through their nostrils.