Wyndahoi saiduse the real thing. Hands free cumming is a mind game for most men. You have to really like the guy in order to cum just from his cock smacking your prostate.☝That's most of it.
Find a man. Fall in love.
With my first guy it didn't happen until after he and I had been together 4 years... with me fucking him. It changed EVERYTHING about our sex life. Up until then he'd been the top 75% of the time. After his first hands they became easier and easier for him. Before we realized what was happening I was topping 75% of the time. I've only had it happen to me 3 times dammit.
The best position for us was missionary where his cock was between both our lower abs for extra stimulation. Eventually we discovered using a real hard pillow under his lower back to make it arch was even better.
I checked your profile to see your age, 27. You're young enough to retrain your body to re-learn that orgasms and ejaculations are controlled by two separate nerve systems. This will allow you to have 'dry' orgasms that are super intense and can happen in multiples. Guys are using prostate stimulators made specifically made for this. Brand names are Aneros and Mangasm. I've tried but must be too old. However my 22 y/o grandson has been doing it for 4 years now and has reached a level where he can have multiple dry orgasms and hands free ejaculations with his partner of 2 years. I've met others who've reached that same level.
There's a small forum about it. http://www.malemultiple.org/
Prostate massage productshttp://www.aneros.com/category/prostate-massage/
Video of a lucky guy having multiple dry orgasms with aneros.http://www.redtube.com/399769?utm_source=www.bing.com&utm_campaign=embed&t=0
There's quite a bit of information about it on the internet. Just do a search. There's probably info on youtube.