The environment, for one. It's very summer camp-esque, what with the Mystery Shack and the woods, the lake, the pool, etc. Sneaking off to a secluded spot, skinny dipping in the lake/pool, getting tribal in the caves, having Wendy slip through their attic window while trying not to wake Mabel, heck, even having Wendy babysit them.
Wendy herself is still a teen, and while it's a joke that she's experienced in dating, there are certain things she could be experiencing for the first time, using Dip as her wingman. Stuff like sneaking beer, exploring uncharted areas of town, being the babysitter, getting kinky in public (say during pool hours,) etc. Stuff a more mature gal like Frankie wouldn't think twice about. She's also a cool chick, more apt to goad Dip on and then laugh it off. Not straight up dom like a Vicky.
And that's not to speak at all about the supernatural element. Have them switch bodies, clone each other (and parts of each other,) use the size changing flashlight in all kinds of creative ways, control each other with the neckties ... the list goes on.
Boring? Not by half kind sir.