This kind of fanfiction is completely inappropriate. April O'Neil is a character in a family - friendly franchise. Fanfiction should enhance the positive aspects of the source material, like exploring the teamwork of the turtles, their growth, and their relationships with other characters in a healthy way, rather than creating such offensive scenarios.
Fanfiction involving inappropriate or non - consensual themes like this is not appropriate. The Teenage Mutant Ninja Turtles franchise is aimed at a wide audience including children, and such content goes against the spirit of the original work. It also violates basic moral and ethical standards in the fan community.
No, it's not a proper or popular genre. The idea of 'April O'Neil sex with turtles' is not only strange but also inappropriate. The main focus of TMNT related fanfiction should be on positive aspects such as their adventures, relationships in a friendly and family - like way, not on such improper content.