Veil Blue to Kuchinashi no Hanataba

Mugi Hinata has had a physical relationship with Suku Oumi, a popular professional Go player, since their school days. They can only meet when in heat and have yet to become lovers. Even so, they are happy just to be together. Then one day, he witnesses shocking news about Oumi..? (Source: Fusion Product, translated) Note: Includes an extra chapter.