If Vaughan gets his sexual highs from actual car accidents, what does he do for casual sex?  Predictably, Vaughan's sexual acts are themselves a kind of recreation of an accident scene.  Vaughan's library of erotica draws from a different set of stimuli.  We first experience this in the following two scenes.

Firstly, we have Ballard and Vaughan driving to the airport garage, a garage populated by prostitutes.  Vaughan clearly wants a sexual release, and having Ballard with him allows him to have sex in the car while it is moving (Ballard drives, Vaughan can get in the back). 

This linking scene to the actual event is once again important since it gives us yet another splash of humor to break the mood.  As Vaughan negotiates with the prostitute, he notices she's chewing gum. 

"Let's get rid of that. I don't want you blowing it up my urethra."  He says. 

Curiously there is an ad-lib, or late script change at this point, with the prostitute replying:  "Yes Daddy." 

After negotiating sex for $60 (or $150 if Ballard gets involved), they take to the car, and move out onto the road.