Titan’s Bride, The vol. 4 (Yaoi manga)

The Titan’s Bride Manga Volume 4 features story and art by ITKZ.

Hoping to find a solution to their marriage bed problems, Kouichi and Caius head for Alpheine, land of the elves. There they meet Reil, a sex researcher, and Dyne, a mysterious masked giant. With Reil’s guidance, the couple learns more about one another, and Kouichi decides to pick up a new skill: magic!