I sifted through several books on Dubya and the Bush family, but couldn't find any mention of the origin of the nickname in them. (Specifically, I studied the TOC and indices, then speed-read many promisiing passages for sources, but found nothing. I really couldn't bring myself to fully read the books, as the subject matter doesn't interest me that much.) Unless I come across better information in my general information hunts, I'm afraid I'll have to leave sourcing on this point to others. ~  (talk)