when i have intercourse at the peak stage my penis shrinks.i dont know what happens..a sudden spark through my body and penis shrinks which i am not able to explain..not always..this has happened about 5 times..i have been married since april 6 2014. but when i masturbate there is no problem.
Degree understand your concerns went through your details. I suggest you not to worry much.  You have not given your age. Most of the sexual erection and shrinkage problems are mainly due to undue anxiety about sexual intercourse. For you this happened about 5 times. Married for almost 4 months. How many times this did not happen? That is what you should count on. Count positive aspects and remove anxiety about it. You will succeed. Psychotherapy techniques should suit your requirement. If you require more of my help in this aspect, Please post a direct question to me in this URL. http://goo.gl/aYW2pR. Make sure that you include every minute details possible. I shall prescribe the needed psychotherapy techniques. Hope this answers your query. Available for further clarifications. Good luck.