you and Jackson hangout 24/7 to the point where they can literally say anything without making it weird. Most of the time Jackson was at your place, he usually lays or sits anywhere and mind's his own business while other times you two talk for hours.

One day you were laying in bed while scrolling on their phone, as Jackson laid his head on your stomach. Jackson started measuring their stomach with his fingers as he wonders.

You: "what are you doing?"

Jackson: "math..."