I'm glad that most of this manga is showing them during their relationship. I prefer these to the ones where confessing is the end game. Those ones just feel like the mangaka trying to stay serialized.
Also, I think that last shot is to show that she isn't lonely anymore, as, at least when guys masturbate, they use tissues, and i guess the same is for girls? And the trash being empty and tissue box being full means that she hasn't masturbated.