feed back into
feed (something) back into (something)
To try to re-insert something into a machine. Good luck feeding that paper back into the printer—that thing seems to have a mind of its own!
feed something back into something
to return something back to where it came. I tried to feed the stamps back into the machine, but, of course, they wouldn't go. The machine made too many boxes, but you can't feed them back into it!