system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When I have a full bladder during the night, I sometimes dream that I pee. What keeps me body from actually wetting the sheets?
gpt
Both nocturnal penile tumescence (morning wood) and REM atonia (a purposeful block from activating normal muscles while dreaming so that you don't sleepwalk or kick your dog or eat your pillow) prevent you from peeing the bed.