Aunt Martha, being his godmother, sends Beaver a gift in the mail: it's a gold ring that belonged to Aunt Martha's brother, Theodore, after who Beaver is named. Beaver, who loves the gift, wants to wear it to school to show all his friends, but his parents forbid him to just in case he loses it. In Beaver's mind, carrying the ring to school on a piece of string tied to his pants is not the same as wearing it, which he what he ends up doing. All Beaver's friends are as enthralled with the ring as he is, but that doesn't stop Judy from goading Beaver into actually wearing the ring to prove that it fits him and therefore is his. Once Beaver puts the ring on, he can't get it off. He's afraid that when he hears Miss Thompson, the school nurse, say that the only way to get it off is to cut it off, Beaver interprets that to mean his finger, and not the ring. Although it doesn't hurt too much, Beaver is more afraid that his parents will find out that he disobeyed them, and that Aunt Martha will find out, she who may no longer love him for what he did.
—Huggo