Forum:Double Summon Effect?

Okay, so me and my friends are arguing over the effect of Double Summon, which I assume you know. He says that he get's an extra summon every turn, even if it's in the graveyard. I tell him it's not a Continuous, so he can't do that, and we ramble back and forth.

So question is.. is Double Summon usable the turn after it's activation?