Potato Please: Hidden Achievement

I don't get how to do the hidden achievement Unauthorized passenger. I get it has something to do with the dog maybe? i really want to bring him on the train :D

i cant do this, is it realy just standign by the square and press E on the bags? if you stand a few feet away from the machine itself, underneath of the bag line, look upward and try to catch the underside of a bag as it goes over you. if you can't see the underside of the bag as it goes over you, move back little by little until you can see it then hit and hold E.