Many anesthetics actually have an amnesiac effect as well. If you’ve ever been under general anesthesia then you likely had a minute or two of talking with the anesthesiologist that you will never remember and that last “this is just oxygen” moment is not actually the last moment you were conscious.

Alternative read. They’re into watersports and do this at home. He’s holding it because he wants to wait to get home so he can relieve himself that way. She’s teasing him about being unable to make it home to enjoy it. It’s not actually a matter of being uneasy about public restrooms, just the much more understandable discomfort with that sort of activity in public.