Uh...yeah no, that's not going to work.

Mabel knows who you are now and that you used to be friends. Which means that you're stuck with the both of us. I really wasn't joking about that befriending thing. And we're sort of a package deal. Especially in strange places where it's just the two of us.

[Which means, creepy or not. Dipper is not letting you off the hook on this.]