The female act of touching herself furtively in the privates while fully clothed; so-called because of the reputation Bostonians have for sexual inhibitions and hypocrisy.
It was a long and boring guy flick, so I entertained myself by Boston jilling during it. I don't think my guy was the wiser, as he was too intent on the action.
by Nora O'Shaughnessy November 19, 2007
Get the Boston jillingmug.