I’m trying multiple-cursors in emacs.

When I select a word, I press M-x my/mark-all-like-this, the selection works fine, then I press Ctrl-g, and my cursors move correctly backward. When I use back space it delete properly the text for all cursors, but when I write something it only write on the first cursors. What am I doing wrong?

I use it in emacs mode. In evil mode it’s worse.