Curiosity

i only have ten count, because none of the manga i've read have been translated into english.
and i don't hide them, it was actually my mum who bought them for me.

I buy them after i read them online :)) Esp when the story is interesting and i cant wait for translation haha. I mostly buy Japanese manga, cuz English ones are damn ex, and not so many titles either.
Aout displaying, the ones with little to no smex scenes i just put them on my bookshelf, the rest goes to my locked drawer :))))

where do you buy yaoi mangas aside from online?

I buy them at a book store like Thalia or Hugendubel (when they have some, not all of them have mangas especially yaois) or at my next comic store. They have almost all yaoi which have been published in Germany.

Ich hab mal ebend nachgezählt und es sind stolze 73 BL Mangas :D
Für gewönhlich kaufe ich nur Yaois, die ich noch nicht online gelesen habe, denn warum sollte ich sie noch kaufen, wenn ich sie schon gelesen hab ^^ Aber es gibt da ein paar Ausnahmen: z.B. Finder und Katekyo hab ich gekauft, nachdem ich sie hier online gelesen hab :)
Um auf deine zweite Frage zu kommen: Ich habe alle in mehrere Regale verstaut und noch ist etwas Platz übrig ^^

I have around 15 yaoi at home, because my sister reads more of them than me and started buying them earlier (so she has more, I guess around 50 or 60)
I (we) actually always read them online before buying, because although in France we have a lot of series available, the translation is crap. Also, finding tankoubon is easy in specialized shops (which are, what a coincidence, 5 minutes away from my home :D ) or in big big stores like the fnac.
Unfortunately I had to move to another city for my studies and it has only one shop, and in it exactly 18 yaoi for sale. I'm speaking about the volumes, not the titles.
My sis displays them in her room at my father's home and hides them in our room in my mother's home. All of mine are hidden at my father's (no more room at my mother's). Our father never goes into our rooms so it's not an issue, but we do argue as to whether it's safe to leave them in the living room (which she does and I believe is shortening my lifespan due to intense stress).
To hide them: under the bed is a classic, or else in classic bookshelves but you double layer it (like, you put clean books in front and yaoi in the back). If your parents don't check your closet (I'm assuming you want to hide it from your parents) then in the back under that pile of T-shirts you never wear is a good place.