When I am watching video podcasts in iTunes video is very slow to pause ...

I have some interesting video from iTunesU on my iMac iTunes server
and sync them to the iPad where the video is mobile and wonderful,
but ...

When playing, I tap and tap on the screen sometimes and the video controls
will not show up, like if I want to adjust the volume or scrub to another
location, rewind, etc.

Is there a secret to hitting the right spot, or does everyone have this problem?
Is this just a tweaking problem with interrupts inside the iPad OS or is
something wrong? Is there a way to get the controls to stay on screen all
the time so this does not happen?