What Causes Electric Shock Feeling Inside Penis?

HI..

I got a sudden shock inside my penius before I start to mastubate, I was tired so with internal pressure I was making tight my penius, suddenly i got this shock and penius went numb and shrinked may be two days after that i got erection in morning, after this incident a week later i tried mastubating again but i could not ejaculate also penuis shrinked before ejaculation but I felt ejaculation inside,, and in unrine also there is no semen, after three day during morning stools may be because of pressure all the semen came out through penius. please advice what has went wrong,, there is no pain anywhere...