I used to musturbate alot not always by shaking my penis but i used to hold it and rub it multiple times in a day in my pant because i used to watch alot of porn and stuff.but from past 2 monthsim facing a severe problem dirst of i penis sensitivity is gone secondly musturbation feeling is gone it feels as if the sperm is going back in when i prolong musturbation just a little to feel more by watching porn thirdly on the left side of my penis veins get really huge when i prolong musturbation just a little this was not thecase before and also my penis bone gets hard when even its not erected.i have tried everything but the feel is not coming back and it feels like my sperm is going back in and all the feeling is gone when muaturbating please help me i beg.