when you do the following.
Hold out one arm outstretched, and palm-side up. Now, let the wrist go as far downward as it can while your arm is in this position. (kinds like your hand is in a position to push something, except upside-down of what it would be in if you were going to push something). Now take your other hand and place it near the middle of that arm and hold your arm with it. Slowly move that arm up until it is up and past the wrist area. It feels really good the closer you get to your wrist.
Also, another thing that sometimes (not always) feels really good for me is if I try to lick as far back in the roof of my mouth as I can, and slowly start to go towards the front of the roof of the mouth. At some point it starts feeling really good.
Okay, well, lol, maybe I'm weird, but it feels good to me

Each is a unique feeling, too, not like any others (that I know of)
*Edit* Maybe this should go in L&R forums area ???

...or is it in the right place?
PS,..I just thought about something too. This might only work (give you an effect) if you have super senses. In other words, if you have very acute senses, especially the sense of touch.