Headcanon: Post-series, Wendy gets really close with Pacifica. They're talking about ghosts one day and the topic of Dipper's first ever ghost encounter comes up.
Wendy: "Oh man. That's sounds sick! No offense. It's just.. nice to see the twins in action y'know? Wish I was there to see it. *sigh* I remember the first time Dip went up against a ghost. It's crazy how he improved that fast."
Pacifica: "It's bound to happen with the kind of antics they get into. Wait.. you said improved. How'd he get rid of it the first time?"
Wendy: "Thankfully for us, we didn't do anything too bad. Just pissed off the old guys for doing 'teen stuff'. They let us go when Dip admitted he wasn't a teenager and did the lamby dan—" Wendy tries to stops herself, but it's already too late.
Pacifica: *face full of glee* "..He did the what now?"
Wendy then proceeds to try, and fail to recover the situation. Pacifica promises to not say a word to anyone.. anyone but Dipper that is. What? Wendy didn't specify. Bending the rules is a Pines family staple! Pacifica teases him over it while playing Bloodcraft: Overdeath. I would write how, but the vision isn't coming to me rn.