Discovered this morning that there was an actual drive-in movie theater here that showed porn. My auntie told me this when I was a kid (because she was that kind of auntie), but I had moved here in the 80's and by then, the theater was down.
This porn drive-in was confirmed on the current Facebook meme, involving flashbacks with "You know you're from...", and I happen to be someone who is from the Tri-Cities in Washington State. Like any drive-in, you'd pay your admission, take your car in, park, and do what you do when you watch porn. Apparently this was big in the 1970's and early 80's. In its place today is an area/neighborhook called Queensgate, where you'll be able to find Walmart, Petco, Target, Home Depot, and a bunch of restaurants.
A with regular drive-ins, if you didn't have enough to pay for admission, you'd stand out of the gate/fence and watch, either by sitting or standing. I can't imagine people going to this porn drive-in at sundown, and specifically wacking off by the fence to Vanessa Del Rio or Linda Lovelace.