I'm really not fond of princess abusing the full moon.
Since Aki is forced to lose self-control, it feels very similar to all those stories with taking advantage of a drunk person.
It would be different if she agreed to being "moonstuck" beforehand, but that was Momo's doing.
They even mention that there are laws against inciting others.
I won't go so far as to call it rape, but Aki definitely wasn't in a right state of mind to give consent.