He is just busy, busy, busy with wiggling, and sometimes the wiggling takes over the narration as he gets absorbed in the movement (i.e he picks at the yarn ties on the blanket and begins to braid them, suddenly, he's caught up in the braiding, and the fluency of the narration is lost). 
I suggested he use motions that fit with the oral narration the other day, like he's gesturing along with his "speech" he's giving. He did not like this at first, but has now embraced it with gusto.
He uses his hands to gesture like he's puzzled, or shakes his head emphatically "no", or shrugs his shoulders and splays his hands wide in confusion, or crosses his arms when he's angry, or smacks his palm to show a vase fell in the mystery, etc. It's been fun to watch, and he's having fun with it! Best of all, if he did these motions while presenting something to a group, the motions would make sense, look fine, and not detract from his message. 
Anyway, I just thought I'd share this for anyone who may have a wiggly narrator too. In Christ,
Julie
Of course I don't allow that which then messes up his narrating. I'll try your suggestion, but acting out things has not been a strong point for him so far.
It took everything in me not to loose my gentle and meek attitude the Lord so graciously helps me keep 
Bless his little heart