And I would agree with you if this was that. But this is art of the female form. Although it's not surprising that you don't understand this at your age. As far as my son masturbating? I wouldn't care. Masturbation is very natural and healthy.
Fantastic photo, it feels as if she is an android from a cyberpunk movie (even more so becasue you chose to hide her eyes .. the most "human" element in photos) ... even her tattoos could be mistake for an android model number .. and sorry if that was too nerdy XD