Also, seems like some people don't understand the punchline (idk if I'd say it's a punchline though), but here's how it goes:
- The clerk got embarrassed because she accidentally revealed that until now, as an adult, she still tries to pester her uncle into setting up another authentic nagashi soumen setup.
- She was so embarrassed that she acted silly (getting all wobbly and had to cool herself down using wet towel)
- After that, she explained the reason why she's very interested with nagashi soumen setup
- The teacher got too distracted by her silly antics and wasn't really listening to what she said