Cherub 2: "Hey mom, these are my babies I think" (while holding each one of his balls).
Me: (Babies? Oh, boy. Pondering just letting the moment pass with no words), "those are actually your balls".
Cherub 2: "They are? Like my eyeballs?"
Me: "Kind of. Those are your private part balls."
Cherub 2: "Hey, they both have b sounds in them! Balls! Eyeballs!"
Me: (Glad to speak phonics instead of balls), "Yes, you are right. Cool!"
Then, on to something else. Easy as that!