>>16368287If you use sketch you will learn the last move used by the pokemon you sketched.
So you can find a wild smeargle, use happy hour, it will sketch it, then you catch it. Or you could go into a double battle, have your smeargle use happy hour and have another smeargle you own use sketch on your smeargle that used happy hour. In both cases the smeargle with happy hour needs to be faster than the other one of course.