Wean on
Definition 1 of 2
Pro Tip 1/3Start Gradually
Weaning on involves a gradual process, not an immediate switch. 
She started weaning her son on green vegetables slowly.
Pro Tip 2/3New Experience
Wean on is often used for introducing new experiences, especially for babies or young animals. 
Kittens are weaned on to solid food at around 8 weeks.
Pro Tip 3/3Parental Context
The phrase is commonly used in contexts related to parenting or caregiving. 
Parents often wean their toddlers on to new textures in food.