It's a story about the sexual awakening of a young boy and girl, though not in an intercourse type of way. It mainly consists of Rika tellling Sakura to show her his "boobs" in various public places and expressing a desire to make them grow. She likes his "girly" (i.e. embarrassed) reactions and has been slowly training him to be comfortable with the idea of wearing a bra. It's also implied that Rika masturbates to the thought of Sakura (ch. 3) and she seems willing to reciprocate boob-love at least on some level, like she describes her nipples to him (ch. 5).
Sakura's head of hair seems way too big and it looks stupid. Rika's hair is cute, though it does feel like it never moves. The facial expressions also feel a bit too same-y.
[Reviewed at chapter 11]