Kyouken Hachiko summary:

Hachiouji Jou, the mad dog, is making a name for himself in the delinquents circle for knocking out various strong delinquent leaders... And his next target, apparently, is Himemiya Seishirou, second year leader of Asanagi high school and a "cat lover"? But as soon as they meet, things take a different turn and an initial attraction leads to steamy sex and some apologies. So who is this Hachiouji who bears resemblance to Himemiya Seishirou's beloved dead dog, Hachiko?