Truck him and feed him beans.

Get on feeBay, you'll have a couple rolls dropped off on your doorstep in a day or two.

I've not heard of anyone trying this but if you don't mind sacrificing some film in the attempt:

And it's just an idea,

Cut your piece to fit. Without peeling the film apart, lay it against the outside of the window and gently warm it with a heat gun until it stretches to shape. An extra set of hands would help.

Then, with the film stretched to shape, peel off the backing, spray your soapy water and apply.

Anyway, it might be worth a rty. If you do, let us know how it works.