Torticollis seated side flexion on a stability ball ('Torticollis' Cervical side bending AROM, sitting on stability ball)

Sit your baby on a stability ball supporting them at the pelvis or trunk.
Roll the ball from side to side, tipping your baby with the movement.
As you tip to the right your baby should side flex to the left to right themselves.
Repeat this movement to increase activity on their affected side.
Tipping your head at the same time will help to encourage the movement as they will try to copy you.