So I just got this deck containing two Duskwitches and one Skybooster Squadron.

Duskwitch makes it so all my creatures come into play ready.

Skybooster Squadron has the ability Reap: return Skybooster Squadron to your hand.

So if I have a Duskwitch in play, I can just play Skybooster Squadron, reap with it, return it to my hand and repeat the whole process six times. Thus gaining six Aember a turn with just these two cards.

Opponent should make sure to kill the Duskwitch as soon as it hits play.

Rule of 6 is play AND/OR use a card 6 times, which means that playing Skybooster Squadron counts against the Rule of 6 as well as the reaping, so you can only do this for 3 Æmber (3 plays, 3 reaps).

(For a good example of the rule of 6 in action, showing how both playing and reaping count, you can check out Crucible Cast Episode 8 using Drummernaut and Ganger Chieftan)

Still Really good at 3 times, though

Yup, reasons like this is why Duskwitch rarely survives a turn.