In Smart mode

Change the Bounce intensity limits from Settings > Soothing > Bounce intensity limit.

Move the level slider to the right to increase the bounce intensity for Levels 1 - Level 4. Level Gentle will always stay at 3%.

You can temporarily change the Bounce intensity from the home screen by tapping the Soothing bar, and adjusting the level slider. The new level will be in effect until baby changes sleep state, or you can lock to keep that setting for the amount of time your lock timer is set for.

In Manual mode

Change the Bounce intensity by tapping the Soothing bar and moving the Intensity slider to the left.