It sound like you are jealous of your roommate, or more feasibly, in love with your roommate and jealous of the girls? Have you tried telling your roommate how you feel about him?
I think you need to gradually work your way into position to get into his pants. Here are some steps that I would follow:
1. I would start by telling your parents that you are gay. It might be awkward at first, but how do you think your dad, having no idea about your sexual preference, would feel walking into his basement and seeing you playing naked leapfrog with the bag boy from the local Safeway? (Side note: when they offer you "help out" they are only offering to help you take your groceries to your car)
2. Buy some plastic trash bags, duck tape, a few rags, ether, heroin and Calcium Oxide. I would recommend buying these products at varying locations and on different if possible. You don't want anyone thinking anything suspicious if happening. LOL!
3. Now, when your buddy is sleeping put some either on one of the rags and place it over his face. once you are sure he is out shoot him up with heroin, just enough to start getting him dependent on it. You will want to do this for about two to three weeks before the next step.
4-7. This is where it might get a little dicey, so just PM me and I'll lay out all the details for you.
8. Now that it is just you and your emotionally distraught, heroin addicted roommate who thinks he somehow "removed" four girls it's time to give him the ultimatum. Naked leap frog with you or you are going to the police.
I can say that 3 out of 4 people choose not let you go to the police. Them ain't bad odds! Well good luck, enjoy and I'll look for your PM!