They always held hands. It began when Albus Severus was learning to walk, so Cassie held his hand and walked beside him. From that day on, whenever the two of them walked anywhere, they held hands.
Cassie was five when Draco pointed out to her that it really wasn't necessary.
"He's big enough now, sweetie. You don't have to hold his hand when he walks."
She looked at her father like he truly didn't understand.
"He's mine, Daddy. My Albus Severus. So I hold his hand."