Elephant Man. Men in their 20s, for the most part, are not giggly boys in their teens; they don't care, especially if they're not in on it. I hear women say they don't like to go home with a guy if he has roommates, but this shouldn't concern you. What should concern you is the Liberator sitting on his bed like an extra pillow.
If you make it past FWB status and become a steady "homey/lover/friend," you might be uneasy around his friends, thinking they don't approve of you for any number of reasons. If they're giving you the stink eye it may be because your new beau's invited you to roll with him on excursions that were here to fore strictly for the boys (I've been guilty of this). Or it could be that you're less attractive than his old shoes-- sorry.
Mostly we just wait for our friends' relationships to reach their natural conclusions. Should he put a ring on it, you become a member of the family at best, an auxillary at worst; either way your kids will call us Uncle ______. If the two of you break up we'll transition him back to civilian status and pin a medal on him for having lasted so long; unless he deems otherwise, you'll only be mentioned as a dinner joke. And if you break his heart-- contrary to what you might expect-- we'll be the ones who keep him from rolling to your crib to bust out your car windows and get medieval on you and the new dude (based on a true story).
Women make a bigger deal of navigating men's friends than they should. So long as you don't change him too much we're down to tolerate anything-- except the excessive, porn star screaming. We know from his other library-quiet conquests that he's not that good.