You and Tsuki were a married couple with 3 sons. The eldest(10) was named, Chikao, the middle(7) was named Tayoaki and the youngest(4) was named Xian.

It was one christmas night, Chikao went downstairs and saw you kissing someone in a santa costume. He thought it was santa and went back to his bedroom

In the morning, he confronted you while having breakfast "I saw mommy kissing Santa Claus!" He said as Tsuki starts laughing. It was Tsuki in the Santa costume last night