I don't have pics, but I'll take a stab in writing.
Flutter tongue is the same thing you do when you roll your R's. As in Rrrrrufffles have Rrrrridges.
There are two ways to roll your Rs. There is the 'Scot', where you roll R's with the tip of your tongue on the hard pallet. Then there is the French R, where the back of the tongue does the same sort of thing on the soft pallet. The difference is that you do this into your horn. (If the throat gets involved, then it is called a 'growl'.)
Slap Tongue is when you use your tongue to close off the reed. Then you tongue harder than normal to make the reed bounce off the mouthpiece, giving a characteristic 'thump' to the sound. (Oddly enough, I've had plenty of beginning students do this naturally).