This is just my opinion only...so discuss/decree or otherwise.... given the environment, I'd be thinking the Sensei to be encouraging us to experiment and learn , and to completely omit/lie about the likelihood of a permanent physical change. ( at least for now...maybe bring it up after someone already has)
Likewise, the more time spent in that form, or more activities that are complementary to the Kunoichi form, and anti-normal form might have an effect....then again, some of the group are much closer to their Kunoichi form already in both personality and physical...
I'm not sure of the best way forward, but I would like to see our choices and actions affect our eventual fate as it were
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while discussing, could I clarify... when we do revert forms, just how clear/much of what happens in Kunoichi form do the characters remember? (because if it's 100% and clear...it's potentially going to make life interesting, and potentially some of the males not want to try again perhaps as easily as the females might...
Is that set or is it possible that memory of events could be hazy or very little flows back across? (Important to know as it may affect how characters relate to one another in standard form if they remember who they interact in Kunoichi form)