Aka Mon basically follows the same pattern of most Japanese imports in which one girl is the focus of the entire show - the one exception being that Shirasaka takes it up the butt.

First she warms up her pussy with her fingers. Then she is joined by a dude who gives her lots of oral, generously finger fucks her, puts his dick in her mouth for just a bit and then proceeds to bang her pussy in a few positions. After he pops, he uses a massive vibrator on her clit.

In the final scene, the dude warms up Shirasaka's butt hole, starting with small objects and progressively inserting larger items until she's sufficiently loosened up for his dick.