Well, imagine a girl who goes into a haunted house with her friends as a dare. In the dark corridors, she feels a strange tug on her clothes. Turns out, there's some sort of mischievous spirit that gives her a wedgie by pulling at her skirt and underwear. She panics not only because of the wedgie but also because she's in a haunted place. She quickly tries to fix it while looking around nervously for the source of the spookiness.
There could be a story where a girl is lured into a haunted house by a mysterious force. Once inside, she experiences all sorts of strange happenings. One of them is that she suddenly gets a wedgie as if an invisible hand has grabbed her underwear. She's so terrified that she can't even think straight about how to deal with the wedgie at first. But then she musters up the courage to try and adjust it while trying to find a way out of the haunted house.
One possible girl haunted house wedgie story could be about a girl exploring an old, spooky haunted house. As she's running away from a ghostly apparition, she trips and gets her underwear caught on a nail, giving her an accidental wedgie. She has to struggle to free herself while still being scared of the hauntings around her.