Doesn't seem to be in common use. Google claims 28 hits but only shows nine, six of which are a repeat of a single citation in which it seems to mean "to laugh." The other three look to be your "common" (if three out of 8 billion can be considered common) definition. As to an etymology, I'd WAG that it's from gee and haw, commands to a draft animal to turn right or left, respectively. But WAGs don't carry much weight in the field of etymology. Ask at wordorigins:

http://p098.ezboard.com/bwordoriginsorg

They have a much better handle on this sort of question .