Hi, Thanks for writing in. At 23 years, it is a normal practice to masturbate as long you do not over do it. Please see that your masturbation is not affecting your daily activities, studies and job. Coming to specific questions asked by you: 1: if i see some type of sexual thing i get erect but then goes non-erect and this process repeats while i see sexual thing for example porn movie. is it normal? This is normal occurrence and should not worry you. It is the autonomic nervous system (sympathetic and parasympathetic systems) at work. It is the way your brain perceives sexual material and reacts to it. 2: i ejaculate before erection some time when i do more. is it because of too too much masturbation or some thing other?? You should not be preoccupied with masturbation. Sometimes, you may ejaculate without full erection and this is not a disease. This is again due to the autonomic nervous system at work. Hope this helps