When I was yonger I did it a couple of different ways. The first was a rope climb at the gym. have to be careful not to stain. The other way was doing chinups. The effort of keeping my core strong massaged my prostate. Then a variation was to do pullups using the bedroom door. The combination of the above and the friction of the door used to be get off very quickly.
Now I don't know what you consider hands free, but I have used a cock pump to get it hard and then masturbated my cock using the rubber ring.