Selfish but Adorable

This the story of childhood friends, Natsu and Shuuji, who finally come together.

Oneshots in this manga:
Vol. 1 - Please Express it Properly and Noise Nostalagia

Vol. 3 - Futari Yuugi
Mayumi is always having his boyfriends stolen by his twin Masaya. So why does he always introduce them to his brother, knowing what the outcome will be? Why doesn't he especially miss them when they're gone?