Perhaps a demonstration

If she wanted you, she could come to you. Seeing her so obviously turned on, you grasp your cock in your hand and start to stroke yourself. Olive watches intently as the pleasure of running your hand up and down your length sends shivers down your spine.

For once you don't seem disgusted at the idea of masturbation. Maybe because this hot girl was staring at you while you did it.

Speaking of which, you notice her hand trail down between her legs and pull her tight dress up slightly, revealing gorgeous black lacy underwear. She quickly pushes her fingers inside it and starts playing with herself, mirroring you.

"Fuck. We should not be doing this... But you're so fucking hot. Just. Stay there, I can't help it. I have to cum..." She moans as you watch her desperately playing with herself, leaning back against the wall as you can hear how wet she is.

The sight is too hot. You start stroking yourself harder, the feeling of your huge cock in your hand is driving you crazy. You feel massive and realise one hand isn't enough. With both of your hands on your cock there's still plenty of flesh exposed and Olive gasps watching you double fist your own monster.

"Oh fuck yes, stroke that big fucking cock. Show off for me" she gasps, not taking her eyes off you. "If I'm showing off for you, it's only fair you return the favour." You grunt as you run your eyes over her tight figure.

Without hesitation she pulls her dress down, exposing perfect breasts. Even better than you'd ever imagined in any fantasy. Perfectly round, sitting close together and high on her chest despite being quite large. You feel your cock pulse and swell in your grip. It's too hot and you're going to come, you can't stop yourself.

You're shocked as you feel the massive girth suddenly increasing as your cock expands, ready to explode. Before a burst of thick cum flies directly at Olive. It splashes against her chest and she screams, her eyes rolling back into her head as she joins you.

Another burst follows, and another. You stumble forwards, coating her completely with more and more layers of the creamy substance. As it pours off her face and breasts.

She stands there, covered in your cum looking shocked. Breathing hard you watch her legs just shake with aftershocks for a moment. Wiping her eyes clear she simply says "I need a shower"