The grandchildren were over the other night, and I was on the phone
talking to my son. Not noticing that one of the boys was close enough
to hear my comment, I said "He's just blowing smoke up your ass" to my
son. (About someone who wanted to sell him something)
After the call, my grandson asked why someone would blow smoke up
there. (He knows what "ass" means) I danced around the question with
the usual "It's an expression that grown-ups use."
It got me wondering, though, about how such a saying came about. Some
internet sources say it goes back to the practice of giving tobacco
smoke enemas. That was a new one on me, but it was a real thing.
http://engineerofknowledge.wordpress.com/2012/04/05/do-you-recognize-this-medical-instrument/
As an aside, my grandmother firmly believed that blowing cigar smoke
into the ear would alleviate an earache. My grandfather, a cigar
smoker, was glad to oblige. My grandfather used to tell her that
pouring warm human urine in the ear worked better, but that was never
tried. I was never sure if my grandfather was serious or not.
--
Tony Cooper - Orlando FL