You ever wake up late and so thirsty that brunch becomes a fevered beverage fest and you’re sipping down coffee, water, milk, juice & pop all at the same time? We actually love this as it gives us a chance to show off our entire collection of glasses and mugs.
So, Professor, a 'ship' is basically shorthand for 'relationship', and shipping is the act of enjoying a relationship between two individuals. So when someone says they ship you and Yveltal, they're saying they'd like to see a relationship between you. The 'x' is just a convention, a way to write it out, like 'Xerneas x Yveltal', or, another way, 'Xerneas/Yveltal'. . . . Also, seriously? You and Yveltal are old as balls and you've never considered doing the doo-wop-diddly together?