You don't "use" Wario. You BECOME Wario.
It's subtle at first, you want to beat the game with all the characters, so you bust through Classic with the big W. Pretty fun, gotta love that bike. Later at dinner, you add more garlic powder than usual on your pizza, and devour half of it much to the chagrin of your family, but hey, you were hungry!
Then you're playing with a few pals. Having a bad Shiek day. So, hell, let's just troll them a bit and bring out the WAH Machine. Suddenly, gimping Ike seems a lot easier, and was he always so fluid in the air? That night, you decide to skimp on the shower, after all your manly scent is the only thing you need to reel in the babes (though you could swear you were starting to pack on the pounds...).
Now you're in training mode all day trying to nail down bike throw physics. Why can't anyone find a reliable combo into the Waft??? Maybe if you practice a few more hours you can figure one out... Of course, you fail to notice your body hair growing at an exponential rate as you clack away, and your sinuses are acting up something fierce, feels like your nose is just swollen to hell, but you don't seem to care at all. In fact, your mind is far more focused on thinking of how to swindle your pal Jimmy out of the $500 he just won in the lottery.
Finally, you're at the big tourney. At this point, it's hard to tell where you stop and Wario begins, you're instinctively "WAH"ing along with your main as you rack up the damage on 'Puffs, Luigis, Bowsers...
And then comes the wall, the Smash pro who has your number hard. Outmaneuvering your aerials, hammering you down with projectiles, anti-airing you with up-smashes to kill. And you panic, and Wario panics. And you know there's only one way to win, the WARIO way.
So you open your maw wide, and swallow his controller whole.
And that, dear children, was how I was evicted from PAX.