Y is for “your choice” so I picked: Timeout (resting habits that they take up after being stressed)
Kageyama tends to get lost in his own head sometimes which just compounds problems. To combat this, he will find a quiet place (sometimes stashing himself in a closet) and take 5 minutes to inhale and exhale deep breaths, his eyes closed. The lack of continued stimulation allows him to focus on the root of whatever the problem is and either solve it, or just having the break to push it away to be dealt with later.