In the Docchi mo Docchi series:

V.1 - どっちもどっち Docchi mo Docchi
From their offices high up in a corporate skyscraper, alpha males Ozaki and Tsuburaya make all the ladies swoon. Ozaki's known for his irresistible pheromones, while Tsuburaya's a noble, worldly genius. But when these two rivals end up in bed together, who will come out on top? It's seme versus seme...and much more than pride's on the line!

V.2 - どっちもどっち! ! Docchi mo Docchi!!
At long last, the battle to become top dog - literally - produces a clear victor. But who will it be?

V.3 - どっちもどっち! ! ! 第三のイケメン Docchi mo Docchi!!! - Daisan no Ikemen

V.4 - どっちもどっち! ! ! 厄介なイケメン Docchi mo Docchi!!! - Yakkai na Ikemen

V.5 - どっちもどっち! ! ! 覚悟のプロポーズ Docchi mo docchi!!! - Kakugo no Propose

V.6 - どっちもどっち! ! ! ないしょの遊び Docchi mo docchi!!! - Naisho no Asobi

V.7 - どっちもどっち! ! ! 過去からの刺客 Docchi mo docchi!!! - Kako kara no Shikaku

V.8 - どっちもどっち! ! ! ひとつ屋根の下 Docchi mo docchi!!! - Hitotsu Yane no Shita

V.9 - どっちもどっち! ! !～家族になろうよ！～ Docchi mo docchi!!! - Kazoku ni Narou yo!

V.10 - どっちもどっち! ! ! Birthday Time
Docchi mo docchi!!! - Birthday Time