Wake up next to your unguarded childhood friend to slowly stimulate her, making her more aroused over time. You can wake her up when she's aroused and start to have some actual fun with her. It's a bit difficult at the start since it's supposed to be slightly more realistic, a little bit of patience is required, but the art and animations are quite a good reward for when you wake her up aroused.
There is good sound design, you feel immersed when listening to the sound. The girl has some silent dialogue, so she has some things she says in speech bubbles like in manga, it gives a pretty good idea of what she wants or how she feels. The game can be played manually or semi-automatically so you can enjoy it as you want.