My penis at sometimes pulsating when I am lying still or idle. It lasts for few seconds, but I didn't feel any sort of discomfort or pain. Do I have any problem? What is this? I am asking this of you because I'm conscious of this and it bothers me a lot. Please help me sir.
It is quite normal. Most likely you are seeing or feeling your heart beat through your penis. It generally happens when the valve for inflating the penis is closed or semi-closed and your heart beat is strong. When you have a really strong erection, your heart tries to force more blood into your penis, but there isn't room for any more. The result is a pulsating feeling that is in time with your heart beat. If you've had your blood pressure taken, you realize you can feel the beats of your heart as the pressure is slowly released by the cuff. A similar thing is happening with your penis.
Another possibility is that a muscle is spasming, which also is not unusual.
The pulsating feeling is nothing to worry about.