I received a charming email from Puppy updating me on the condition of his balls... And, it seems I did manage to fool him by mailing him a penny instead of the key! In his words:

"Wow! You really fooled me with that mailing today! I thought sure it was the key when I reached into the mail box. It was my envelope and it felt like a key inside. You are wonderfully and ingeniously cruel! And I love it!
So far the only problem has been restless sleep at night from being so erotically turned on by having my balls locked up. It's like being in a low intensity session with you that just goes on and on, 24 hours a day."

Hmmm... With all that in mind, I might just want to keep the keys a little longer.