I usually don't mind somebody taking a glance, but a couple of weeks ago I finished my workout and decided to swim. I was just rinsing off when one of the guys from a grade 12 swim meet that was taking place at the gym came in. I wear N2N swimwear, so I know it is fairly revealing, but he did not stop staring the whole time. I would look over at him and he just kept looking.
He followed me out of the showers and went to his locker, which as it turned out was close to mine. I grabbed shampoo and went back to the shower hoping that he would be gone by the time I returned, but he followed me again! I was weirded out that anybody could be so intent on looking . In the end I figured that he was just curious so I decided to strip thinking that it would satisfy his curiosity and he would stop. It didn't work. It was honestly the most uncomfortable I have been in a locker room and the most freakish that I have felt. I felt like I was in a circus sideshow. I was tempted to say something, but I did not even know what to say. I dried off quickly and changed and got out as quick as I could.
I have got to a point in my life where I still will not walk around nude for hours on end and am still a little uncomfortable with guys looking even in the shower, but I am more accepting of it and every now and then almost enjoy a little (short lived) attention.
My advice to you is to get used to it if you are nude in the locker room. Guys will look, usually though, it is a glance and not a 5 minute thing.