Common steps and sub-activities
This is a do-it-yourself approach, although given that you are using equipment, someone else could use it for you.
I will not be too specific here as there are any number of machines on the market that provide ‘stimulation’ via electrical apparatus. The advantage is that this too can be ‘hands free’.
Sitting on a spin dryer works [no sorry I’m joking – or maybe I’m not]. I have heard a probably apocryphal story of someone who went into a trance state on a bicycle with a very narrow saddle going down a bumpy road. They fell off eventually.
This method is cross referenced from the activity of Sexual stimulation.