Source- https://www.dlsite.com/maniax/work/=/product_id/RJ01042304.html
The rest of Waiwai Seisak stories here https://www.dlsite.com/maniax/circle/profile/=/maker_id/RG41427.html

Premise- "In a fantasy world where women are completely naked, there were those known as sex sorcerers."

Sex Mages—these were those who wielded magic that controlled sex.In a certain fantasy world, guilds commissioned sex mages to perform secret quests, and the work was carried out in secret.
One sex mage responded to a wide range of needs, from adventurers' troubles and illnesses to requests from powerful figures and even accompanying them on their journeys. Tonight, he once again accepted a secret quest and will perform sex magic on the bodies of female adventurers...