Yeah, I noticed that too. Do you use Directional Influence? Edit: oh. Meteor smash. Nevermind.

Are you referring to inputting a direction when you block?

When someone hits you, there's a sort of technique to influence where you go during knockback. Everyone calls it DI, or directional influence. Example without DI: Fox hits you with his up smash. You go straight up and off of top of the screen, easily losing a stock. Example with DI: Fox hits you with his up smash. With proper DI, you don't just go straight up. You fly diagonally upwards towards an upper corner of the screen, increasing the distance your character needs to fly to die and decreasing the chances of losing a stock.

Hm... I was not aware of this. It can't be as simple as using the move stick right? Because if it is then it hasn't been working for me. I know i can move whilst falling but bit whilst being knocked back.

It's not as simple as holding the control stick in the opposite direction of where you're flying, but you have the right idea. You have to hold it perpendicular to the direction that you're about to fly(counter-intuitive, I know). And if you try to do it while you're already flying, it won't work. You have to do it during the hit. This means that you'll have to either have good reaction time or predict the attack before it happens. It's simple but it does take practice. It's something most players haven't intentionally used before and It's only used commonly by the competitive smash community. In smash 4, you can only use it after the newest update :) Also, I don't think it's usually that useful for when you get sent below the stage, which is why I said never mind.