Rhyming all the time

He sings them to himself. "Doffer, noffer, naffer, daffer, daffodil."

He greets us with them: "Daddy Baddy! G-ma B-ma!"

He uses them in sentences: "It's my bottom pottom!"

He greeted me one day with "Mommy Tommy Bommy Wommy Pommy, can I have this?"