Oh ya, being passive aggressive (well it is) and hoping HE will want it and bring it up and make it happen so you don't have to be brave isn't usually the best way to go. I imagine now people give advice to watch that Showtime poly show and use that as a reason to bring up poly? If its not a show you'd naturally watch or you would feel it was too much of a stretch to draw comparisons between them and what you wanted (mff triad and a mfmf quad), you could peruse this list
and see if there are any that might be more natural for you to watch with him.
I'm just gonna say, if you are too scared to say awkward and hard things, you may find it a struggle to navigate being poly. If it's just this first suggestion to bring up a possible dynamic change that's the hurdle and you think you can handle being honest after that point, it probably wont be so bad. Get a couple books from the website and book recommendation list, they probably have some ideas on how to communicate this stuff.
Or just practice a brief speech. "I have fun when we spend time and play with X - do you ever think it might be enjoyable to do more than just play with him since he is a good friend? That thought came up in my mind and I wanted to talk with you about it and see what your thoughts were on it."