But anyway, once they have formed the plan Phoebe points out that this means they can do the plan laugh, which is basically an evil laugh which follows the creation of a good ol' fashioned evil plan. Usually used by villains such as Bond villains etc.
It goes a bit like this, "Muahahahahahahahahahaaaaaaa"
Joey: How does that go?
Joey: Oh I get it, wohohohohohooooo...
Phoebe: It's not Santa's plan.