A Strange question

[suz1000]

We have a Savannah Monitor. When we got him on July 26th 2013 he fit in the palm of my hand. Now he's about 8" (he is genuinely growing in leaps and bounds). He is healthy on a good diet, regular vits, feed him in a separate cage give him a bath once a week etc.

He's picked up a rather crazy habit. He's pooping on me when I pick him up to hold him. I'm not terribly bothered by it but it tells me maybe he is still really scared of me. Can you help me to understand this behavior and maybe give me some handling tips so he and I can overcome this. I don't mind the poop but it grosses out my wife and makes her pretty upset (for the record: its much better than the biting)