Something weird happens as soon as you decide to write with your left hand. At the beginning of this experiment, you are all tens with squeezed fingers and muscles. It happens from time to time that you forget what you want to say as you are so concerned with writing.
Frustrating is what it is.
You might think after 5 minutes that you are becoming worst so then sleep on it. You might also feel sort of a pressure in your right hand. That's because your brain is sending commands to it to take over the hard task.
S and 5 are particularly hard. You want to start [writing them] from opposite side.