Yao Lan

Hi mummies, anyone using yao lan for your baby? My nanny has pampered my baby by carrying him to rock him to sleep. Now my baby needs to be rocked to sleep. We gave in and bought the yao lan. I read about shaking baby vigorously causing internal brain bleeding. The max speed for the yao lan is 4 and my husband uses his hand to shake the yao lan faster and lower, he says baby likes this and sleeps faster. However I am feeling worried if the up and down movement will affect my baby.