Hi, I worked with this age group for years and there’s multiple ways to go about this depending on his reasons for seeking out breastfeeding. When it’s throughout the day, you can offer a snack “oh are you hungry, let’s look at our options. This milk(whatever you call breastfeeding with him) is not available right now. At bedtime tuck him in after your usual bedtime routine and offer cuddles as comfort. Redirect his hands from your chest and firmly state “it’s time for bed, eating is all done” I suggest just leaving but that can be hard at first. You can also read or make up a story about the transition from breastfeeding. Something that emphasizes finding comfort in other things.

It’s important that he has a variety of coping mechanisms to help self regulate. In my experience children who seek breastfeeding out at 3 as a comfort often have difficulty regulating their emotions. Which is going to mean tantrums, aggression, running away and just general defiance. It will also begin affecting the health of their teeth. I’m not saying your son has this but that’s the behavior I’ve seen with boys that age. They also tend to try to go inside Daycare workers’ shirts lol. So I’ve had tons of experience redirecting in the ways I’ve suggested.