Not a terrible first animation!
What I liked best, was you had a decent joke, and got right to the point.
The parts to work on, are obviously extra frames of animation, the artwork itself, and environment.
Extra frames would help your characters seem less stuck in the 'prone' position, with only their moving parts showing life.
To help this not be so noticeable, you could draw an extra frame or two for his body, even if his body isn't going to move at all as he's talking, and cycle between those 3 frames, so his lineart wiggles a bit, giving a non-artificial, subtle movement to his demeanor. It just works.
Hopefully you carry on the clever humour with your progressing flash works. Keep it up! :)