There is nothing wrong with looking at others' bodies and penises are a very interesting feature.
You do not say how old you are but shyness over showing one's genitals becomes more ingrained as we get older and is particularly prevalent among young men, especially those who fell they are under-equipped in the genital department. This is often a mistake as penis size when flaccid is no indication of size when erect!.
Ones which are big when soft usually grow very little as they erect.
2 ins is not particularly small, I have seen much smaller ones than that and they have all become around 6 ins when erect.
I attended a school that taught first grade to 12th grade so after swim class boys would hit the showers. Me for my age, about 12 years old, did have someone of a smaller penis and a lot of the other guys my age. Often, the shower would fit about six boys, there would be little boys, like first-graders and second graders and then some boys of my age. I definitely would look at the boys my age and their penis size so as to compare to mine. The funny thing is that there would be first-graders that just happened to really large penises for their age and sometimes bigger than me and that made me feel somewhat awkward. When I live with my uncle and his adopted son, Josh was seven or eight years old and we would often go swimming naked as well as showering together I realized that he had a very impressive penis size and so at school I didn't let it bother me any. And yes there were times, only when there were boys of my age in the shower, it wasn't a new for us to sometimes masturbate. Not something we did every time we showered but I did so to be cool like them.
I grew up pretty much the same way. We swam naked at school so I saw all my friends penis and scrotum from age 11 to 18. It was nice. We jacked off together and often each other. A few blow jobs happened but most of us got married and have kids and grandkids now. It was fun
NOTHING WRONG WITH LOOKING AT YOUNGER TO COMPARE BUT LET IT STOP THERE NO TOUCH GO INTO STALL AND JERK OFF
I ALWAYS CHECK OUT PECKERS AT THE BEACH SHOWERS AND WHEN I START GETTING ERECT I GO INTO A BOOTH CHANGING ROOM AND JERK MY SELF OFF THEN GO OUT BACK IN THE SHOWER AREA TO SEE MORE AND BE SEEN