You walk along Cynthia's soft, warm tongue. The cozy cave that lies just beyond her uvula seems to call out for you. You won't survive this trip, but you don't care. That wonderful gas is all you need. It's worth your life to get just one more breath.
You lie down, and Cynthia closes her mouth. She tilts her head back, and you slip willingly down her throat. It's so slimy, and wet. Despite Cynthia's size, her throat is quite tight, and you just barely slip down. There's a long way down, and it's probably going to take minutes, possibly an hour at this rate.
That's ok. You'll get to her heavenly gut eventually. You can smell it.