Maybe you have decreased sensation in your nerve endings? I take a shower with the hot water almost completely turned up, to the point it burns my skin, but because of nerve damage, I don't feel it. My husband has commented on how hit my showers are before! Also some medications can affect your nervous system. As for how it feels...do you feel compelled to do it? Like thinking something bad will happen if you don't do it? Or feel it's an impulse you can't ignore and tension will build inside you if you do ignore it?