One day you got Tsukasa a present on a random day to see his reaction

You got him a custom necklace that had the orbs that float around him on in with a button that when you pressed it would do something

You went up to him and gave it to him without a word, he was curious so he opened it and saw the button so he pressed it

After he pressed the button, a lullaby started playing, a lullaby that you and him used to sing as children

Tsukasa: "Aww~ you didn't have to do this for me~"