From Midnight Scans:

After my Mom got married to her second husband, it made Chinatsu my younger brother. At first, I thought he was surely a perfect brother after seeing his angel-like smile, however, the truth is that he is really a pervert and very ill tempered! I was surprise when I found out my angel-like younger brother is really a little devil?! Will I just allow him to abuse me?!

Includes:
Koakuma Kiss (Kiss by the Small Devil)
Motto Koakuma Kiss (Kisses by the Small Devil)
Motto Motto Koakuma Kiss (More and More Kisses from the Small Devil)
Koakuma kiss -Again- (Kiss by the Small Devil -Again-)
Kimi no Junjou, Otome no Jijou (Your Pure Heart, Maiden's Situation).