Attached to a fucking machine is definitely best. Attached to a strap on harness would be better, I bet. If you don’t have a fucking machine, try a ball. It could be smaller like a volley ball or larger like a yoga ball. With a smaller ball, try placing it against a wall just below your ass with your upper thighs against the ball. You can slightly lower and raise your body, rolling the ball between your body and the wall, causing the dildo to fuck you.

You can also attach it to a door. Use a bungy cord on one side of the door and a rope on the other.

A Fuck Machine is the best !

/galleries.php?id=2683

My old kinky gf used to stick the dildo on the hood or side of a car, in a parking lot or parking garage and ride it. That was back before cameras everywhere. Nothing hotter than sight of her on hood of someone's car jumping up and down on the dildo. She was on tiny side, so nimble. But I preferred it when she stuck it on the side of the car because eventually I'd pull my dick out and she'd suck me off while banging back onto dildo.

She tried other places, but cars being smooth were best surface to stick the dildo on.