This is a pretty common thing, I used to unwittingly run sets and take attention away from my wings when they were supposed to be doing things simply because I was higher energy... I tried to tone it down but I couldn't, so that may not be your answer. If he's always the one talking and you find it hard to get a word in, be mindful that he doesn't do it on purpose to overshadow you. You'll have to either work on getting your energy on par with his, or getting him to tone his down (although like I said, this is easier said than done).
Let him open a set while you get a drink or something, give him time to talk about this awesome guy he's out with (that's you
) and something you both did together recently that DHVs you both. Basically, have him talk you up like you're the most awesome guy on the planet so that interest is spiked before you join the set. Now, when you come into the set and start talking to him they will be fighting for your attention. Think about it this way, if they're really getting along with him and he loves you to bits, they're gonna share this enthusiasm and wanna get to know you too. It'll work in your favour if he keeps their attention well because you can isolate your target very easily this way and you also have the perfect excuse to - "I can't compete with this guy, he's just so awesome!! Seriously though, come with me a sec I wanna show you something", that sort of thing.