After Harry gets the Marauder's Map from Fred and George he goes to Honeydukes then finds Ron and Hermione standing together by the Shrieking Shack. Then Drako, Crabe, and Goyle come and start making fun of them. Since nobody knew Harry was there (because he was under the invisibilty cloak) he went up to Drako and started messing with them. In one scene he is twirling one of them around while he is pushing another one of them over....you can't be spinning in circles AND pushing at the same time without more than two arms.