Why do I get this feeling when I do this?

OK this is what I do. I swear this is not a joke. I lay down on a bed or recliner. Then i take my left hand and put it in a form as if im going to shake someones hand. Then I put it on the end of my ball sack just before the taint. Then i lightly stretch toward my tip. Then the futher I go them more presure I put and I get an ic feeling and I cant resist it. It is like a 60% ic feeling but not a full feeling. My questions are does anyone else know about this? Does anyone else do this or experiance this? Is this normal? Is there something wrong that this happenes? Any comments pleasr leave them.