Re. 'Gagging away'

It seems to be an American expression. I did find a use of it from 2002.

My favourite example is from the Wall Street Journal 13th August 2003

"Ben Curtis, who won last month's British Open not quite gagging away as the field gagged even more, and Thomas Bjorn, who in some parts has ..."

The article is titled Returning to the Scene Of the Choke Hill Crime

It is behind a paywall.Google search provided the snippet above.