Take the moon stamp on the stool in front of you and use it on all of your clothes. Now even if you sell or lose a piece of clothing, you'll be able to find it again by checking for your special moon stamp.
A few days later you're with a friend when you recognize the clothes they're wearing. You grab it, rip it off, and scream, "F**k (ふく) you!" There is your moon stamp! These are your clothes!!