uhm your missing half the point of being a freshman you should be bringing tight freshman girls back to your room every night then the roomie doesnt ask any questions....
i got lucky and my roommate took morning classes and i took night so i had the room from 6 to 1 before class and since i was the night owl roommate so id wait till he went to sleep and rub one or two out never got caught because he sleep like a log and snored like crazy
For me it was late nights in bed/in a sock, the showers, or when he was at class. By mid October of my first year, he and I got very close so it was no longer an issue