Masturbation will not cause reduction in size... it's not a disease it's just a desire...it's ok if you masturbate once or twice...too frequent masturbation may cause you problems....try to avoid frequency by distraction methods like yoga,meditation,listening to music,by doing activities you like etc. masturbation now is regarded as a normal, healthy sexual activity that is pleasant, fulfilling, acceptable, and safe. It is a good way to experience sexual pleasure and can be done throughout life Masturbation is only considered a problem when it inhibits sexual activity with a partner, is done in public, or causes significant distress to the person. It may cause distress if it is done compulsively or interferes with daily life and activities...consult psychiatrists they will do the needful..