i checked in this book at the library a while back.

i don't know how to read
japanese, but gather around kiddies and uncle mike will tell you a story about what seems to be about being clean.

don't eat while you're taking a shit. because for some reason your friends will be very crossed when they find out about your eating habits/bowl movements.

heed these warnings from your uncle mike or you'll start to feel sick with the possibility of, but not limited to, mud butt.
at that point even your friends, who were crossed at first, will start to feel sorry for you.

then for some reason they'll be waiting for you outside with a feast ready with the chef holding a bar of soap.
maybe they're your friends and they want to throw a party for you.
or maybe, just maybe, they are really assholes who are rubbing it in your face that you had painful diarrhea and know that you won't be eating anything anytime soon, so they throw a huge fancy party because you can't eat any of it.
the end.
moral of the story? it's not, "don't eat while taking a shit." do it up. do whatever feels comfortable for you. be yourself.
the true moral is to find some better friends, possibly some whom share the same eating habits as you.
don't you just love japanese children books?