I think I'm in stage 4 of puberty. I have hair around my penis, under my armpits, legs, arms, and some on my face. My penis hasn't grown any bigger or wider since I was 12 or 14. Also my testicle are not that big either. Will my penis and testicle still grow if I'm in stage 4? Also is there a way that I won't get erect seeing other guys penis in the shower?
Lupe (age 15)
The increase in circumference is subtle and you probably will only notice it when you are fully erect. Being in stage 4, you may gain a little bit more length, but not much. You are close to your final size. At 4.5 inches you are at the low end of the normal range for an adult man, but you are still normal.
Testicle size varies a bit being in volume between 16 and 27 milliliters (typical for stage 4 is between 12 and 24 milliliters). You didn't mention what size you think you are, so I can't comment whether it is extremely out of range or not.
In regards to having erections while showering, you need to understand what is triggering them. The primary trigger for erections is sexual ideas. Most of us grow up keeping our bodies private, but in a shower you are naked where others can see you and you can see them. Even though you have no sexual desire for other boys, the situation is enough for your developing and oversensitive mind to trigger an erection.
Then, the action of showering -- having warm water pouring over your skin and scrubbing down -- causes sexual stimulation. It is not just the genitals that are sensitive. You have numerous areas over your body that are sensitive to touch and many of these will bring on sexual feelings.
Finally, erections are caused by a set of small muscles clamping down on the veins leaving the penis. The back pressure is what creates the erections. When you get nervous, you tense up and often during your adolescent days your body tenses more muscles than it needs to -- including the ones that trigger an erection. Most of us are nervous about being naked in front of other people, so guess what usually happens? Then when you realize that your penis is getting hard, you become more nervous, which just furthers your erection.
As you get older, you slowly learn how to keep yourself from getting tense and to distract your mind from sexual ideas. It won't stop all erections when you don't want them, but it will help to decrease them. So when you are in the shower, think about some problem you are trying to solve -- something as far from sexually themed as you can get, such as math. Also, keep your eyes above the waistline. Men are visually stimulated and this way if one guy gets an erection, hopefully you won't notice and have it trigger an erection in you.