‘School Days’

A shy and unconfident teenager, Itou Makoto, has resigned to stealing glances at a cute girl as they ride the same train each morning on their way to their high school. At least until Saionji Sekai surprises Makoto and chances a peek at a photo-snap of the beautiful Katsura on his cell-phone. After evilly teasing Makoto about his hopeless crush, Sekai offers to support him in his romance. So after many Makoto-pep-talks and lots of scheming, the three become close friends. Close enough that Makoto braves asking Katsura out on a date. And she agrees. Later that day, Makoto finds a quiet moment to express his thanks for all support that Sekai has offered him, and makes clear his intent on finding a way to repay her kindness. But he is totally unprepared and very surprised at the reward that Sekai has chosen. Sekai steals a long kiss from his lips, before breaking away to run for the train. Sekai turns and wishes Makoto well on his date.

Descriptions taken from AniDB.net