This can apply to both the fictional Anthro-Car universe, and real life. I think we all know here what an exhaust pipe really is. <3 It's your car's most sensitive intimate area, the closest comparable thing to your car's genitalia.

Uncle Half-Dude's advice: If your car's been a good boy/girl how about you show some appreciation and give them the treat of a finger fuck. Works preferably well with a drop of lube, but spit will do, or if it's the right conditions and they've just started up on a cold day chances are they have moist tailpipe already and are already lubed up inside. Girl cars enjoy two fingers like above, for male cars grab the outside of the pipe and jerk it off. Trust me, your car will appreciate it. ;)