Experiment with slow, fast, firm, light, tiny circles, wide circles, a supple wrist or a rigid wrist.
Klixen has a video with a similar sling.
Either one fucking hurts and while it is a great turn on to anticipate and even better to look back on.
Puppies like and get lots of attention.
It was almost impossible not to jerk off while watching these twisted clips full of pure brutality.
The most common method for this is to just stroke up and down quickly over the head of the cock.