An abbreviation of the sexual fetish for 'Fucking Against a Window'
The act of taking a parnter with either their back or front against the window. Usually from behind so that the partner's face and chest presses against the window, for women meaning their breasts press against the pane.
Often mixed with the fetish for exhibitionism as one can clearl see the people through said window.
Can also been used in cars where the space is often limited so it's likely someone will be pushed against the sides.
We were doing in the living room last night as she pulled me over to the back door, so I pushed her up against the window pane and started F.A.W.ing her from behind doggystyle so the neighbours could see from thier garden.