These are casting techniques that the pro’s use to fish heavy cover. The flip is a very short cast where you do not even reel in the line.
Pitching is an underhand cast where you use the weight of the lure to swing the lure out to a spot is 10 or 20 feet away.
Here are a couple of videos that will show you how to do it.
Wired to Fish
Tim Horton does an exceptional job of educating viewers on the basics of flipping and pitching in bass fishing.
Sit down, relax and kick your feet up while Greg Hackney shares his deep passion and knowledge about shallow water flipping and pitching. Hackney posits that big bass thrive in matted grass nearly 365 days a year (except for the spawn) and that all hardcore bass anglers need to fish.