C-c C-j turns your ansi-term buffer into a normal emacs buffer where you can copy/paste. C-c C-k switches it back.

So, for example, if you want to paste text into your ansi-term session, you’d copy that text from your emacs buffer, switch to your ansi-term buffer, hit C-c C-j, then M-y, then C-c C-k.

If you use emacs and you’re not using ansi-term and screen, you should give it a shot.