Sheath Shoujo ~Aloof Girl is Thrown Into Another Parallel World~ v.1.07 / 納刀少女サヤ ～クール系陸女 異世界の宿場町に放り込まれる～

A "sheathing sorcerer" is someone who can use the mucus membrane of their inner body (you know what I mean...) to impart special effects to those who touch it. It's an especially rare skill. Many of the people meet with horrible fates so as not to disrupt the power balance of the world.

People often kidnap them to use them for their own nefarious purposes. They're often sold into slavery and bought by the rich. Others, still, are forced into prostitution... Theirs is a cursed lot capable of driving many to madness, themselves included....

When track runner Sayaka gets sucked into another world, she finds little hope of making a new life for herself besides becoming one of these "Sheath Sorcerers". Selling her body every day just to eke out a living, slowly her reality takes a turn for the depraved...