DISCLAIMER: I have no idea if specified equipment can be used in the manner described safely. This is, after all, a fantasy.
*****
She reclined in my passenger seat of my Dodge Magnum. Her skin was flushed, and her breathing was faster than normal.
I reached for her left hand and held it.
"You can still call this off. Little one."
"No. I am ready."
I gave her an reassuring squeeze, as I pulled up my car to the gas station and carwash. It was already dark. I had slipped the owner an extra hundred this afternoon to leave the carwash on, telling him that I had something kinky planned with my girlfriend in the carwash. He nodded in understanding. He had no idea what I really have planned.
I left the engine running as I went around to the passenger side and helped her out of the car. Her robe parted and her long legs revealed themselves for a second, then she stood straight and took a deep breath, and nodded.
I gently pulled the robe from her shoulders and tossed it back into the car and closed the passenger side door. She stood in the dark, naked with only a distant streetlight illuminating her.
I took in her slender form, her small breasts, her long dark hair. She hugged herself in the night's chilly air, goosebumps already forming. I checked in my cargo pants pockets for lengths of rope.
I guided her to the front of the car. She sat on the hood, then leaned back. She raised her wrists, and I slowly secured her wrists to the sideview mirrors. Then I got several cargo-tie bungee hooks that hooked under the trim to secure her ankles in place, attaching them to the rope, so she's spread-eagled on the hood of the car.
I left her there for a moment, to contemplate what may come next, then I went for the water hose next to the car wash. It was normally for clearing the caked on dirt on the vehicle, but I had a somewhat different purpose in mind.
I turned on the water and tested the nozzle, then turned it to spray. I walked back to her, and without a word sprayed her from top to bottom. She yelped and squirmed, but she was not going anywhere.
I reached for the long brush used to wash the wheels and started scrubbing her, paying extra attention to her breasts and between her legs. She shook her head left and right, and whimpered.
I switched the nozzle back to stream, and pelted her with solid streams of water, with a few extra seconds between her legs for effect. I turned the water off, and checked on her.
"How are you doing, little one?"
"I... I... I almost came. "
"You will not come yet, little one. I haven't given you permission. Remember, do not face up, face the left side." I smoothed her wet hair away from her forehead, then went into the car and drove it into the car wash.
The car wash was the old style with rotating brushes, not one of those newfangled "brushless" car washes. Though I wondered what would one of those feel like on her skin. I filed that for later as I closed the driver side door, went to the control panel, and started the short wash cycle.
I walked around the machinery to be beyond its range of motion on the car's left. I know I'll get wet, but that can't be helped. I need to be near the emergency control panel with abort button, just in case.
The water soak cycle started and sprayed down the car. She shivered at the cold water and sputtered for breath.
I called out to her in the temporary silence as the soak cycle finished. "Little one, turn your head this way and close your eyes." She blinked several times, but obeyed.