From Bakeneko Scanlations:

"When we met, I fell in love with you..."
The novelist Sakaguchi was troubled. When Sakaguchi took in a weak kitten, the high schooler Kazuya, who comes to the his house to visit the cat, suddenly confessed. He thought it was just childish nonsense, but while usually being quiet, the Kazuya who is confesed his love awkwardly while his ears became red, seemed cute to Sakaguchi. But... adult love also entails sex, right?
The love between the rough novelist and clumsy high schooler.