Itazura - Ijiwaru Tenshi悪戯　イジワル天使; Ijiwaru Tenshi; Tease - The Mean Angel; Mischievious Ill-natured Angel; Mean Angel

[From ShoujoMagic]: Ijiwaru Tenshi Ayumi is a high school student. Her friend's brother, Shouma, is younger than her, but he looks handsome and older! Shouma asks Ayumi for her digits right off the bat, and he's smooth like a player--not really Ayumi's type. The more time she spends with him, though, the more she likes him. But is Shouma really sent from heaven... or is he just a tease?