"...we made love in my Chevy van..."
"...If this van's a rockin', don't come a knockin'..."
"...My name is Buck, and I like to fuck..."
Though the term is used positively, it is usually not a good thing to own a pussy wagon, as they most often are gawdy and repulsive.
The term is rarely used by anyone other than the car's owner.
see also: rice
Guy 2: Dude, your truck's hideous. Scrap it. Now!
Another Guy: "It was great I made out with Jess in the pub"
A Guy: "I thought you were going out with Charlotte?"
Another Guy: "Yh, and? She already knows that I have also had a thing with Hannah, it is not like a fling with Jess will make a difference."
A Guy: "Your such a fucking pussywagon!"