Indeed, she is feeling more and more close to her son, still fighting the conflict of the taboo but breaking it at the same slowly time, something she wouldn't do with others just him other than her husband. Getting scared by that realization as she gets aroused and shows it with her nipples.
I like that the relationship is progressing even if sometimes it's slower with her son because is her son but she IS feeling it and enjoying it and they have been sharing a lot of stuff together, even masturbation and an intimate foot massage she was completely enjoying.
Haha possible though for what I understand that happened in the other path he immediately closed the door after interrupting the shower, so...who knows, I doubt it but maybe.