There are a lot of people, young teens or mostly not so young teens that are trying to control their erectile functions and most of them seem to have the premature ejaculation problem - if you are a young guy and you think that you have this type of problem ask yourself - how much time can you last before ejaculation comes? If you last more than 5 minutes, then it's kinda cool and you may not have any more problems with it. The fact is that young teens with premature ejaculation tend to ejaculate within ~2 minutes and becuase of that they think their women may not be satisfied in bed and because of that they tend having some big problems, sometime bigger tham themselves - self esteem problems and desperation are the biggest ones, and then comes confidence - it's better to have a good relation in your couple, so that you're going to play it nice and your women is going to understand that at first, most likely if you're very young, you can do it to long, so she has to understand (if she loves you and she wants to get marry with you, she'll understand).

   There are some couples that do have some infertility problems because of low sperm count, so they say - the basic fact is that sperm quality is the basic thing and it's very important in order to have a quite and good baby. 

   Tip: you can't stop the moment of climax, because is something natural, the thing you really can do about it is to understand the fact that you can delay the moment, with some psycological work and also some pc muscle work - which is basicaly the same muscles that are helping you to piss or not to piss - there are a lot of exercises and methods available that are going to help you out.

   Is known that sexual positions are the best and some of the methods in order to play with your premature ejaculation problems - the fact is that if the women is on top you have some chances of not being so sensible and not getting it out to fast. 

   Why is women on top position good in order to help you last longer (I don't know, it only depends on you, you have to try it and understand the fact that each one is different and if something's working for you, it's not necesary to work for someone else) - the penis is not going to be so stimulated is the woman is doing all the job with it. 

   Biology and psychology are hand by hand in the climax and ejaculation part - the pc muscle is going to be contracted for 1-2 seconds or more (when you ejaculate) and the fact is that you could control it, if you really want - the fact is that you need more practice and if you are just younger in your 18 or early 20's, then there is nothing to shame to be about. There are a lot of husbands with erectile dysfunctions and I would recommend that you better take some natural herbal pills (chinese are one of the best in the business) or use some natural methods (nlp, tantra, kegel) in order to make it done, instead of using some drugs to play with your chemicals in the organism.