Logic tells me that a pharmacy or department store would be most likely to have the necessities - that is, lube and condoms and the like, and they might even have peanut butter and/or chocolate sauce besides :Db - but I'mma hafta second bishonen_girl on the book store option. Book kink? What book kink? I don't have a book kink >_>...

...Also, it probably already happens all too often in the public bathrooms, so I'd avoid those on principal.

Also also, I'm tempted to suggest skating rink blanket scenario or something :3