Tipping a disc is when you poke the disc with the tip of your finger to pop it back up into the air to keep it in flight. Often, this is one of the first tricks someone will learn after the basic throw and catch. One subtle difference, however, is that many people begin by tipping the disc while it is above their head with their palm facing down or out. Here Ryan shows a more advanced version with the palm up and the disc directly in front of you.
Basically, give yourself a flat throw with lots of spin. Then curl under your pointer finger, hold it with your thumb, and point the remaining finger upwards, with the palm up. Then, tip the disc in the center, over and over. Not too hard, just enough to keep it under control and in front of you.
This is a handy skill that can be placed anywhere in a series of tricks. For example, set the disc under your leg, then tip it. Also, this tip can be made more advanced by adding a restriction. Tip it under your leg, behind your back, or in a bad attitude position. If you want to see how far tipping can go, check out this video of Joey Hudoklin. Might be the most hein tipping combo ever.