Toilet-bound Hanako-kun is a supernatural comedy (at least in this first volume, and according to my googling). It's licensed by Yen Press. I got this volume via interlibrary loan.
Review:
The students at Komome Academy have many rumors about the school's supposed "Seven Mysteries," the seventh of which is Hanako-san of the toilet. It's said that Hanako-san haunts a particular toilet in one of the girls' bathrooms, and if you summon her and give up something precious, she'll grant you one wish.
Nene Yashiro wants Hanako-san to grant her wish to have her crush fall immediately in love with her. She's shocked when she learns that Hanako-san not only truly exists but is actually a boy, Hanako-kun. She adjusts quickly, though, and finds herself getting tired of what she views as Hanako's overly slow and not terribly effective efforts to help her. When she tries to get a bit more magical help from Hanako, however, she ends up biting off more than she can chew and is forced to become Hanako's assistant. Together, they investigate multiple supernatural mysteries, including thieving "faeries" and stairs that act as a doorway into a dangerous other world.