My ScreenBeam Dongle gets hot regularly I've noticed.
At first I thought it would be a problem. But since there was nothing I could do to prevent it, I just walked away from it. I also made sure it was free from any obstructions.
Beyond that, oh well...
I have been using it that way for a year now.
It still works great!
I bought a 2nd ScreenBeam for my friend's house, and that dongle gets hot too.
The phone however is a different story.
My phone doesn't like to be touched BY ANYTHING while using the ScreenBeam. If is near ANYTHING except the prop-up phone holder I have, it gets too hot and will drop the ScreenBeam signal.
My phone especially hates being near blankets while using the ScreenBeam.
I suggest using a phone holder that doesn't smother it too much, that way the air can circulate.
This is my only idea.