Be sure to attempt it where in a place where he can't back up!
Maybe the corner of the couch or up against a wall if he's the kind of resistor that you say he is! Remember to just keep doing it, he doesn't have to like it, he simply has to tolerate this neccessary task! (it'd be nice if he liked it, but we can't always have everything we want!) I'm just glad he found a good home!