Sensation radiating in nerves

Why is it always so difficult to find answers to simple questions about human anatomy on the net? Let's see if some nice reader can answer these:

1. Why and how does sensation sometimes radiate along a nerve? I mean when you irritate a certain point along the nerve and you can feel it along the whole nerve. I can sort of understand how sensation radiates down - you pinch a nerve in one place and somehow screw up the data that it is carrying upstream - but how does it radiate up? I can irritate some points between my fingers and feel the nerve all the way to the neck.

2. All the site I found talk about radiating pain, and sometime this weekend when I mentioned that a pleasant sensation can be radiated this way people looked like they didn't know what I was talking about. Is pleasant sensation radiating along nerves somehow rare? I find most of the sensations radiating along the nerves of my arms quite pleasant - it's a very sharp shot of pleasure, stronger than an orgasm but much shorter and more difficult to attain - and have spent many boring lectures and meetings in my life trying to find and stimulate the right points. The points are not always sensitive to stimulation, but once stimulated properly it becomes quite easy to repeat the sensation fairly often during the next few hours. Does anyone know what I am talking about? I find it hard to believe that I am the only one doing that.

The places where I usually find these points are on the inside of the arm above the elbow, and also between the second and the third and the third and the fourth fingers, more towards the back of the hand than towards the front. These seem to be situated on the same nerves, on maybe just on the nerves that are very close to each other.