Anyone know how to get my 4 month old to stop planking her arm when she feeds?? Let me explain...she…

Anyone know how to get my 4 month old to stop planking her arm when she feeds?? Let me explain...she just goes all peg arm on me, stick straight pushing against my chest while trying to nurse, which causes her to push away from me, pulling my nipple, and it hurts really bad 😢 she seems to do this to try and get my let down to come faster I think, but it's not helping the let down it's making me tense up and whereas the first let down would only take like 30 seconds to arrive when she doesn't do this, they take a couple minutes when she does...it's making my nipples super sensitive and they hurt for most of the rest of the feed...I've tried redirecting the arm to a different spot so it isn't pushing against me, I've tried holding her hand to distract her, I've tried handing her a teething ring to hold, and also trying to show her to push DOWN on the breast instead if AWAY from the breast...not sure what else to try 😔