The phrase "to massage the baby" means gently rubbing or pressing the baby's body to help relax their muscles, calm them down, or promote their growth and development. Full definition
It has hard material that can help protect the finger of the baby or the parent who massages the baby. (checkpregnancy.com)
The beaded design and smooth, flexible texture massages baby's gums and its compact size is perfect for their little hands to hold. (blog.guguguru.com)
The practice of gently massaging babies has been around for centuries, in many cultures (in Indian culture, for example). (romper.com)