Bearded dragon suddenly frantic & poops when held

Question
My son has a bearded dragon, about 7 months old. Today he suddenly started thrashing while being held, and pooped everywhere. 2 more times he has tried to pick him up and he did the same thing. I noticed he has been in the cave under his basking rock a lot today. We did have visitors, but he has shown him to visitors and never had a problem before. His color is good, he seems alert, his breathing doesn't appear fast/labored, he has been eating like he normally does, greens in the morning and crickets in the late afternoon. We are a bit worried he is sick? Or is it just normal for them to thrash and poop sometimes if not wanting to be held?

Answer
This sounds like something freaked the lizard out when he was being held. It also could be that he is not being held properly.  If you go to my site www.reptileapartment.com I have a complete care article on handling etc that should help you.  You can look for it under the name of How to Tame Your Dragon