Most of you have had some exposure to this drill, but it really can make a difference in the efficiency of your kipping pullup. A kip is really just a redirection of the hips used to elevate the body. You can practice your kip on the floor.
First bridge your butt up from a situp position (like the 3rd frame in the photo). This will be your landing position. Don't forget that! Now start lying down and curl your legs toward your head. Notice how the hips and butt rise off the mat a little (frame 2 in the photo). In one smooth movement, kick your legs up and over to land in your landing position. Remember to squeeze your butt! This is a kip!
Practice this a few times smoothly and take care not to be too violent about the execution...if practicing on a hard surface this can take it's tole! If you need a pick me up, go to your bedroom and practice on your mattress, seeing how high you can elevate your whole body with just the kipping motion.
Get back on a bar and do perform the same motion will a sharp tug at the top and voila! A nice kipping pullup.