http://www.dlsite.com/maniax/work/=/product_id/RJ187865.html

I like page.25,26,27,28

元魔法少女復讐奴隷 = Formal magical girl revenge slave

Story :

Magical girls won the final battle. Girls retire from magical girl career and back to their normal life:)

Now they "can't" transform into magical girl in normal life.

So their enemy back go to avenge:(

Girl has been captured, raped, & become into sex slave:(

戦いが終わり半年後。
魔法の力もなくなり平和な日常生活をおくっていた3人の少女達…
そこへ女幹部アリアーネが復讐の為に現れた。
平和な日常が一変、元魔法少女達の過酷な復讐調教生活が始まる。

Once you start working as a magical girl, you never retire.
It'll follow them through milfhood, it may even splash on their daughters, which, will have to carry on the magical legacy.
They can't just simply "Go back to their normal life", it doesn't work like that... ask the Sailor Senshi's or the Precures for example.
In the worst case, it'll blend into your very own soul... right, Kyubey?

Base +4