Truthfully, getting it on in a vehicle does turn me on, like a handjob, blowjob and backseat boinking, but unless you are in an RV or Van or Soccer traveller, getting caught is too damn easy, just ask a NE San Antonio coach and his lady friend in Olmos park.
Or the guys that normally get caught in Brackenridge or the Mission Trail park.
Thinking about doing it is hot, but the heat goes WAYYYY up when LE arrives.