"…Before I did that I wanna know how it feels like and what percent of signals cause pain. For example, 10 pain and 90 pleasure"
Pain and pleasure. Often they are two sides of the same coin, but to properly address the question, we need to understand a few principles about e-stim.
There are a number of factors that will affect the sensation: Intensity, Pulse Width, Electrode Size, Placement and Resistance. Please know that these are not the only factors that will affect your e-stim experience, but these are (in my mind) the big ones.
Intensity. Are you speaking softly or shouting? It really is that simple. The lower the intensity, the less sensation you will feel. Turn it up too high and you may not like the results. If you take your time and find the sweet spot, you will enjoy the sensation.
Pulse Width. Imagine standing on the seashore watching the waves crashing onto the sand. E-stim pulses are just like those waves as they connect with your body. If they are too close together, they can be overwhelming. Spread out too far, they can be boring. Take the time to adjust your unit so you can enjoy each of the individual pulses. Generally, you should start out in the middle and make very slight adjustments until you find what works for you.
Electrode Size. This one is important, and requires that we understand the importance of having both negative and positive poles. I’ll get to the size issue soon, but first we need to talk about negative and positive. For our purposes, you can largely ignore them, so long as you understand that electricity will only flow through a complete circuit and in order to have a complete circuit you need both an outbound and inbound direction. Bi-Polar toys will have two conductive surfaces that are separated by some type of insulator. Both wires will connect to the toy and you are good to go. Mono-Pole toys, on the other hand, have only one conductive surface and must be paired up with a second toy in order to complete that circuit that we discussed.
This is where size matters. If you have a small electrode that you pair with a larger electrode, then you will have an unbalanced output. The smaller electrode will feel much more intense because of the smaller surface area. The same amount of current will be delivered to each electrode/toy, but due to the different surface areas, the smaller toy will feel much more intense while you may not think anything is coming out of the larger toy.
Placement. Some areas of the body are simply more sensitive than others. A gel pad will feel more intense on the head of your dick than it will on your butt, no matter what the intensity level is set at. There are more nerve endings to send pleasure signals to the brain in the head of your dick than there are in your buttocks, so naturally you will feel one much more keenly than the other. Because of this principle, if you are planning to use mono-polar electrodes, you have to be careful where you place them. (As a side note, never use mono-pole toys above the waist. Find some other way to stimulate those nipples!)
Resistance. Resistance is how conductive a given material is. Ceramic is a good example of a non-conductive material (ceramic resistors, anyone?), while aluminum has virtually no resistance whatsoever.
ElectraStim out of the UK has some truly fantastic aluminum plugs that feel incredible, and some beautiful rubber plugs that feel…well, not so incredible. The reason that one feel so amazing while the other just kind of hurts is due to the resistance. Remember the wave analogy earlier? It comes into play here as well. With low resistance, most if not all of the electrical pulse, or wave is felt. With high resistance, only the peak, or crest of the wave is felt which tends to be a stinging sensation.
Resistance isn’t something that will come up very often, since most toys tend to be made of aluminum or other highly conductive materials. When in doubt, stick to metal toys and you can’t go wrong.
The last important distinction between pain and pleasure is purely personal. Is your mind engaged? Are you very sensitive to the lightest sensations, or are you turned on by more intense sensations? It may take a bit of experimenting, but in time you will find the goldilocks combo that is “just right”.