How do i set boundaries? I have tried telling her to stop tweaking my nipples but she stops only for a bit and does it again.
I had breastfeeding aversion, and so some things i just had to shut down or i wouldn't have been able to continue. Nipple tweaking for them can be a nervous/bored reaction, its not neccessarily a deliberate act, and so i couldn't leave it to my kids to stop. I had to physically protect the non-feeding nipple by covering it with my hand or arm and then keep the child's hand busy. I often played finger games with them or massaged their hand or gave them something like a beaded necklace to play with, and often we both played with it.

When cutting down DDs feeds, (or more feeling like i was more in control of them) i moved from 'demand feeding' to set times for feeds. i could prepare myself for the feed at x time, and didn't feel like i was constantly at her beck and call. I was also able to stop feeling like i was saying no all the time, i could say "yep, let s have a feed after lunch". It took a little while for both of us to get used to it, but so much better when we did. If it wasn't time for a feed, i had to keep myself busy and not sit in our main feeding spot. Deciding on a plan and when to have feeds was probably the trickiest bit. I probably scheduled more feeds than needed, but if we were busy and missed one, i didn't make it up, just moved to the next one.

Over time, DD then began to drop them one at a time. e.g. we often headed out or were busy in the morning and so that one got missed more and more and then dropped.