Have a chat about ending it and think if something else to do in place of a feed. Something fun that will take his mind off it

Being gentle but firm. Lots of cuddles but set boundaries too. Offer something else comforting at those times.

Talk about it in advance. Plan a date flying stop. Potentially have a little tradition/activity/gift to signify the end. E.g new special toy they pick out for being a big boy, special milkshake out. If an option your partner may help with any tantrums after the end as they may still hope you didn’t mean it! Still offer cuddles and reassurance once you’ve stopped.
Another thought – is there any need breastfeeding provides for them? Such as calming down when angry or over tiredness and try have some other ideas to help with anything breastfeeding seems to provide

Maybe let him have less each time then cut the morning one out first. Maybe tell him his teeth are getting bigger and are hurting you. How old is your youngest child that you are breastfeeding? Are you able to easily put a small in a drink container of some type, maybe dilute it too.

I always found kellymom.com a great source of information.
https://kellymom.com/ages/weaning/wean-how/weaning-techniques/

Try seeing anOccupational therapist to support you

If it’s an only child then probably only when your milk dries up and it all happens naturally. If you are about to have another child, then make sure your new baby gets fed first and explain why to your older child. Make sure the older child has something to eat or drink or perhaps give an ice block to while you are feeding your newborn, and explain that only he/she is able to have this.
That’s about all I can think of to help.