Yeah. Let her get you off with her hands so you don't attract undue attention.

“Since you asked, baby, how about a handjob. That'll keep me from coming too soon later on.” Jess twirls her hand in her hair. She bites her lower lip, keeping that little teenager face on and shrugs.

“Ok. Most guys like to get blowjobs, but my mouth IS a bit sore from this morning. I'll jerk you off so you can fuck me later.” She strokes your dick again, but this time leaves her hand there. “So do you want me to just jack you, or do you want me to make this a handjob special?” She's still using her valley girl voice, but you groan as she asks. She giggles. “It's always the special,” she says rolling her eyes. She leans over and spits on your cock, then pulls her blouse back. “I'll tell you what; if you can keep your eyes on the road, you can use my boobie to help make you cum. I know you like my titties.” You reach over without looking, and with practiced hands stroke your girlfriend's perky tit. Jess groans.

“Mmmm... Can't wait for you to get home and do me, John.” Her hand picks up pace. “I'd better try to get you off quickly,” she says. Her spit lubrication method has always been a huge turn on, and as you hear the squishes grow more rapid, you shudder. “It always sounds so nasty,” Jess breathes. Your fingers find her nipple and lightly roll. She gasps. “I mean, I guess spitting on it helps the movement, right? Do you like it when I spit on your cock?”

“Yeah, baby. I love it.” Jess beams, then jacks you even harder. You feel your body tense and without warning, you let loose a monster load, jets of cum covering the steering wheel and Jess's hand. You even hear, very faintly, Jess say “Holy shit,” as you continue to ejaculate over her hand and onto your own pants.

“I really do hope you can keep it up, John,” Jess says, amazed. “You've never come like that before. It was fucking hot. And now I REALLY need a good lay.” You smile at Jess. She still looks amazingly sexy, but even you're not sure you're up for a peak performance.