No hands
In a single pilot machine like the Bell 206 it is done all the time. When on the ground, the friction can be applied to help but the primary stick holding device is the pilot's knees which he clamps on the stick to allow his hand to be used in other tasks. Even with fancier devices in other machines, my gut feel would be to have a part of me touching the controls so that I always have positive feedback as to what the physical status of the stick is. It works. And speaking as a former flight safety officer I don't think it is unsafe.
There is one other time when it is OK too. When up at altitude, flying along straight-and-level, and no danger of running into towers, mountains, clouds, etc, the stick can be clamped between the knees for a quick use of the right hand. For something that will take more time, the collective can be cinched with friction and the left hand used on the stick to allow the right hand to be free for writing etc.
There are times when a single pilot has to write things down. You do what you have to do.