Fluxx, please remain on topic, and please, do not double post. If you feel you need to add something, click on the edit button on your previous post, or wait for someone to respond before adding a new reply.
Snuggles, if you mean plain-jane flying after pressing 'f', you just press 'f' again, and your character should drop. If you mean swooping (which occurs after you target someone with melee selected and lock-on), then press your attack button (left mouse button by default) again.
Bear in mind, 'f' is the default key for flying, so you may have changed it. If you aren't sure, just check your controls in your game menu.