Loving this story. Like everyone else has already said, it's so rare to find a story like this, so you can bet I'll be following this story faithfully.

As for some ideas, anything involving ovary/fallopian play is good in my book.

Also, you could have Akane run into some sort of vacuum type demon or machine and have her prolapse get caught. You could then have the vaccuum pull her ovaries out through her tubes. You might also have it suck the eggs from her ovaries this also.

Another idea, if you're interested, is maybe having Leanne(or someone/something else) get shrunk down and invade Akane's ovaries and eggs.

As a slight spinoff from LNV's idea, you could have someone gain the power to open wormholes(or something) and use to torture Akane's womb from a distance. This could also be used to detatch her womb from her body while still keeping connected to it through a wormhole(maybe to rob Akane of her power).

You could have a scene where some kind of creature invades Akane's womb and ovaries before latching onto them and trying to drain them of their eggs.

As a question, do you intend to branch out from just womb play to maybe urethra play, nipple fuck, etc? I'm good either way; just curious.