Nursing a toddler

Erika β€’ πŸ’™ 5.12.15 πŸ’™ 11.29.18
My almost 18 month old has the worst nursing manners and it's wearing me out 😫 I want to let him self wean, but he constantly gets distracted and practically rips my nipples off. What's a good GENTLE way to help correct this behavior? If I try to stop nursing him he flips out, so that doesn't work :/