This Is How It Feels
She started pistoning her glans through his sphincter while arching it upwards within his prostatic urethra, prodding and stretching the flexible walls which caused him extreme stimulation.
Fertile Soil - Chapter 9
With that, the robotic arm made a pistoning sound as that giant purple flare tip was shoved forward under basil's tail, smothering the boy's big black tailpucker. "ahhh..."
Kobold Breakers: Worship from inside
With a piston going back to a control box of some kind.
JizzPaw
The rather heavy device you're strapped to is basically a pneumatic piston. when the timer runs down the piston will push a nicely sized latex phallus into your tail hole.
Be Coul, Will Travel (Chapter 4)
He had his bride secured; there was no need to send sir piston! at least, he thought so. "sir piston, we have an issue" came a radio comms from the battalion's frontrunner. lazily picking up the radio, piston spoke into it with annoyance.
Commission: A Dragon's Travel Trist
In the middle of the circle, the pistons began to move the central gear along the sides. the gems in the gear glowed, and glowed brighter and brighter as the pistons went faster.
Bunny Love: Chapter 4
Once 3 of the four inches were inside her, rose began to piston it in and out of her tailhole, while still rubbing her clit and watching blake.
The Wonder of Discovery
It was so delightfully alien to feel his piston pressed between his own cheeks.
R&D3: The New Boss
The machine instantly sprung to life and thrust its piston forward, burying the fire-hydrant-sized dildo deep into the gaping tailhole. moving at a steady pace, the piston pulled out and thrust back in, slowly, brutally pounding his ass raw.
Chapter 03 - Freshening Up
His fist connected with the piston, turning it into a thousand separate pieces of shrapnel that shredded nearly everything in the test chamber.
Dragon Milking Facility
The attached pneumatic tube hisses as it begins to piston up and down his length, massaging his erection with a perfect, undulating pressure that seems to know exactly how to stimulate him.
Placating the skipper
"and this unassembled piston serves as visual confirmation that this soldier-human male is of exclusive non-grammatical gender that is not child-bearing."