How do you teach and have a more consistent sliding teeter for agility?

[juxtaposed619]

I'm trying so hard to get my dog to slide consistently on his teeter. He has nice drive to the end, and holds his 2o/2o contact quite nicely, but he only slides once in every 20-30 teeter attempts. I've tried teaching him to slide by having him run to the very end, while I was hold the upper end of the board, and then dropping the board. The best method I have used so far was to have him do fly offs on the teeter, and then after he had nice speed, ask him to hold the contact. this worked for a bit. any suggestions? Or other methods?