No it does not do any harm to you.It is normal phenomenon which helps you to get sexual gratification.You can avoid it only if you feel tiredness or weakness or any other complaint.If you do not have any problems then it is ok.

It's probably not going to feel very good after the fourth time unless you have a very strong pc muscle. I recommend doing kegel exercises. I do them nightly and I have noticed much pleasure even after the eighth time in one day! I'm currently seven down for the day and i feel like hercules, so more the merrier here. While doing some research on prematureejaculationcontrol.com I discovered the stronger my pc muscle is the more I can masturbate, at the pace I am working out my pc muscle I should have no problem doubling my number of "experiences" ;) per day within the next month. Good luck and happy stroking.

My erections are not as strong, and I can not ejaculate inside my girlfriend. Plus she says it causes distance between us.???