One of the best orgasms I ever had, came (pun intended) using a long feather duster and a hair dryer.
This technique feels best if you shave your balls first!
There are many different types and configurations of these duster things so you will probably want to try several to get what feels best to you.
Go to your neighborhood grocer, 99-cent store, and/or craft shop and look for the feather dusters. (Hint: look in the broom isle) The craft stores will often have long single feathers, which are also great!
I prefer Ostrich feathers because they are so incredibly soft, but there are many other feather types about as good.
If you can locate one of the feather duster types that are at least 12' long you have found a real prize! I have tried dusters made of multicolor soft plastic hairs, lambs wool, etc, but always come back to the soft feather type.
(At my own risk, go figure!)
I do this only with the greatest of care:
Get a hair drier, set it on low so you don't fry your nads and spend ten minutes or so blowing your stuff with that nice warm air. Don't get too close or you will burn your self and do not use the high setting. The warm air will help stimulate the groin area and heighten the sensitivity of your balls.
Now lie on your back and slowly drag that oh so soft rascal slowly over your cock and balls. It won't take long for you to figure out what you like best. Try using two at once too!
Now lie on your side, bring your legs together and pull them up to your chest. At the same time push your cock and balls down so they now are captured on the underside of your legs. Run the feathers over your cock and balls and then onto your ass as well! Very nice!
What a rush and the longer you do this the more sensitive everything becomes! After an hour or so of this you will blow one hell of a load! I came five times in a couple of hours doing this, no lie!