MIB = Men in Black... so the Black Organisation. Don't you say MIB in english? Sorry if I used a strange name.
Thank you very much. I don't think my analysis is perfect but I tried to put everyone.
You have doujinshis stores in Japan like K-Book. And in some stores like Animate (manga and anime goods shops) or Mandarake (second hand manga stores) you also have doujinshis. But you can't find them in an usual bookshop. A lot of doujinshi are also sold in manga/anime festival/events like KOMIKET.
I would be glad to... but it seems japanese people don't consider this coupling. I have never seen any doujinshi about them and you should have less internet sites about them than Sonoko x Makoto. It's really an unusual coupling. That's why I'm so surprised it's so popular in western countries. o_O