I have read Inside Mari in its entirety and it does not actually qualify as being gender bender even though some sites tag it as such because
Spoiler Alert:
! Mari actually has a psychological illness that makes her beleive she is a man that body swapped with her, no body swap actually occurs!<
! It also has some straight stuff in earlier chapters !<
ame@feddit.org 1 week ago
Inside Mari was my first manga and I love all of Oshimi Shuzou’s work
For a more in-depth exploration of gender-identity by the author I recommend Okaeri Alice.