I m Masturbating almost twice a day for last 15 years. I m 34 now and single. In my entire life I ve never done it using the conventional way of doing it with hands. I always try to press it against something hard as bed or a pillow or hard bind stack of books and rub against it. How much harmful it can be? I believe I m not getting the morning erctions that I used to get. Can this way of doing it affect the size of penis and sperm count?