I am left-handed, and my friend recently pointed out to me that everyone has a right to use my left arm. He proved it from Shulchan Aruch Orach Chaim 27:6, where it says (and they translated):
אטר... שמאלו שהוא ימין של כל אדם
A left-handed person... his left arm is the right of everyone else
I'm now stuck doing (uni)manual labour for my friend. Is there any way out of this before someone else comes along and takes up more of my time?