It happens because of sexual frustration and can be relieved by doing yoga, pranayama and meditation

take proper knowledge about this

For reducing masturbation and porn habbit: Explore and make a list of time when you usually masturbate including factors which lead to it. - avoid same factors at that particular time, e.g. If you masturbate when you are lonely, then try to be with people all the time. - divert your mind from thoughts of masturbation: sit back, relax, drink a glass of water, try counting backwards from 50 to 1. - if you are used to masturbate watching porn, thn block porn in internet connection and delete all the files you have. - do other activities like swimming, walking, any outdoor sports or going out with friends - if you masturbate in shower, take a quick cold shower and get out early. - If you masturbate while sleeping, for some days sleep in the same room with family members or friend. - start exercising hard while you have excess thoughts of masturbation. This is how you will lose energy, feel tired and would go to sleep without masturbation. Urges generally last not more than half hour, you have to divert your mind in this half an hour.