William sputtered a little. "I.. um... well.. I dunno if I really wanna know how to change a nappy, Papa. But I promise I will protect them however I can. "

Sherlock couldn't help but laugh. Thomas was now asleep in his arms, and he came over so William could see his little brother as well.

"They sleep a lot, don't they?"

"You slept a lot when you were this small." Sherlock replied with a grin.