Alrighty this is what I found on Amazon RE: FAKKU Books.
Carnal Communication is available and sold from Amazon and is Amazon Prime eligible.
Shoujo Material is listed as a Pre-Order, with Amazon Prime Eligability. (More about Shoujo Material at the end of this post).
The following are titles that are not sold by Amazon but sold through Amazon's Martketplace, FAKKU is the seller and all books have the note, "Fufilled By Amazon", so they still have Amazon Prime eligibility:
Renai Sample
Welcome to Tokoharu Apartments
Melty Glaze
PuniKano
Alluring Woman
The following are titles NOT available through Amazon in anyway whatsoever at the time of this post (that I could find at least):
Peachy-Butt Girls
Porno Switch
Love Ridden
TiTiKEi
XXX Maiden
The Job of A Service Committee Member
Fresh Pudding
Curiosity XXXed The Cat
Kira Kira (Still a Pre-Order on FAKKU anyway)
Meaty Minxes(Still a Pre-Order on FAKKU anyway)
Ima Real(Still a Pre-Order on FAKKU anyway)
FootNote: Regarding Shoujo Material right now it is a Pre-Order but it is listed as "Temporarily Out of Stock", it says that even though FAKKU has not even received the book yet and haven't started shipping(as of this post) and has a note that once available they will notify you and deliver. Also I did order a second copy of the book from Amazon and I got an email not to long ago saying they apologize but the book release date has been pushed back to March 30, 2016 not sure which hat they pulled that date out of but they said it.