yah , ive heard about that in cosmo once that masterbateing alot can cause quick ejaculaitons along with unability to get hard(not as common as the first one though)
im not sure if not masterbateing for a while will fix it, you'll have to look into it, but just go slow in bed, if you feel like your close, stop for a minute, thats not much advice i know, but thats all i can do
I doubt thats the case. Masterbating can actually prolong sexual encounters. But keep this in mind. If you have masterbated enough to know what really feels good, then you are probably ensure that sensation during sex. So in other words, stop thinking about feeling good and concentrate on your partner. If you are doing things entirely because..... "Ah that hits the spot!" then you are going to hurry your ejaculation along.
The best thing you can do to prolong your encounter is to think of your partner. Work towards their satisfaction before you consider your own. At some point, you will learn a balance and get your timing down some.
One trick I did during my younger years was to pull out, go down and her for awhile (waiting for me to calm down) and then go back in. It worked wonders and made them see God more than once.