Example: Ally.
He's really a ridiculously good camper that unless you look closely makes you think that he's an aggressive, seemingly random Snake.
He just camps really closely.
He mains the trap character. He camps, but he uses the tools to make you walk into his defensive game the way he wants. As though he trapped you.
Getting off-point, though. Mainly, I think it means what works for Snake doesn't transfer to anyone else. EDIT: Maybe Toon Link.
In my time as Pit, coming up on a mere three months now, I've found him to be a lot like Mario. He has an ebb and flow, a rhythm, of pushing the opponent, and then moving back and luring them in. But where Mario can get fully rolling and true combo with juggles, or a spike, Pit just has the advantages of a sword. He can't push as far to aggression as a Mario at full throttle can, but he is able to keep himself covered in more situations thanks to the sword (mostly DAir and ftilt).
I should say I don't think of it as 'highs and lows' of attacks; it's an oscillation to two ends: offensive and defensive. You can land hits in both modes.
This is the focus of my contribution here, though: You want to restrain yourself even when you have the last hit. You call off your aggro not on the opponent's terms / because of what is happening "for you" (hit or block), but on your terms. You stop pressing based on positioning, conservativeness, and just the fact the opponent is on backstep. You use aggro to create room for yourself to breathe on defensive, and in defending, you make your opponent show you his thinking so you can pierce with aggression.
You don't want to fight until one stops working You don't want to press one mode up until it stops working; you want to switch when you're still in your/Pit's comfort zone. You want to push against your opponent like water. It is (I argue) very natural for Pit to shift like this, repeatedly, quickly, countless times in a match (perhaps even indistinguishably to anyone but you), but it will be harder than natural for the opponent to change what he must to counter.
Use each mode to a short length or long lull, you obviously want to mask the wavelength of this oscillation. I think of it like 'holding the middle ground', not advancing too far into the enemy's territory, never giving up all of your own. You try to win all these little battles, building damage, and then the K.O. reveals itself, or comes about by hitting the opponent enough times with FAir consecutively.
I want to argue for this as really referring to something, as I think it has success over and above playing at an opportunistic range. Pit's hitboxes want you to be moving. They want the opponent to be walking into a tipped ftilt, or they need the opponent to be right inside of his NAir. They want that frame advantage for Fsmash or they need an offstage target for his other lacking power moves. These demand a dynamic fighter. Pit is always wanting to move the fight. He can't completely control where it moves, but he adapts with his reliable moveset, if you know to be offensive or defensive.