prepstudinsc: Bliss--
Don't worry about what could happen too much. I agree with all the other posters that you just have to cross that bridge when you get to it. When I graduated from high school, I spent a month in Europe with some other kids from my school on a tour. I never once saw my roomate naked and he never saw me naked.
Even in college, when I lived in a dorm, my roomate and I never saw each other naked, the closest to being naked we ever got in our room was in boxers. One night, however, the college's Health Center sponsored a talk on safe sex for our floor. (each night it was on a different floor in a different dorm) After it was over, they handed out condoms. We got back to our room and he was saying something about that he didn't like wearing rubbers. I told him that a regular rubber was too short for my dick. We were joking about it, but he didn't believe me, so I got a bone, pulled it out and stuck the rubber on it, and showed him. He couldn't believe it when he saw it, and from then on he just teased me (in a friendly way) that had a big dick.
I didn't try to intimidate him with it, I was just stating a fact. I showed him while laughing about it.
If for some reason, you happen to be naked and your roomates on the trip happen to see you naked, don't rub it in their faces that you're bigger than they are. Just act normal about it. When you can laugh and joke about it, just go with it. They will probably tease you about it, but don't get upset. Just laugh with them about it. They're probably going to be jealous, but there's nothing you can do. Guys will always find something to tease each other about, and that's fine as long as it's not malicious. I get teased by my friends at the gym. I just laugh with them and find things to rib them about.
Bottom line....don't worry about what might happen until it happens. And when it does, just act nonchalant about it and laugh with your friends if they tease you. I'm sure you'll be able to find things to joke with them about.
Have a great trip!