Play in public emphasizes different types of bondage.
One tie that I have done in public I really like.
It can be done with a 50ft rope or two 30ft ropes. I have done it with webbing, and with rope.
I start with a shibari style two column tie using doubled rope on the wrists in front of the body. The rope is pulled between the legs and up the back. A midrope tie is done around the outside of the arms and tied off. If I am doing the tie in two pieces this is the point that I will attach the second rope using a cow-hitch to one side of the knot of the midrope tie. I pull the rope to shoulder straps that go under the armpits.
The tie can be done with a boy on his feet. It's constraining, but in very safe ways. The boy gets to watch the earlier parts of the tie which generally puts them at ease.
It's a good tie.