( Let's do the alternate ending to Yuka/Mai first.

I'll start off at the divergence point. :D )

Mai screamed once more as her womb was pierced, the pain coming together with a pleasure that gave her yet another orgasm, blood flowing from her pussy and mixing with her juices.

She looked at Yuka, and noticed she had exposed her own lower abdomen. Mai, beginning to feel tired, her skin starting to pale from blood loss, realized she didn't want to die alone, and Yuka was right that a girl's body was very fragile.

She grabbed hold of the knife in her womb, pulling it out, and stabbed it into Yuka's belly button with what strength she was still able to muster, before pulling up to open the wound farther.