How do i explain it to my parents?

So I went manga shopping for the first time ever. and i bought this bl called hitorijime my hero. my parents are very strict so the moment we got into the car after purchasing, my sister asked, "why are there only dudes on the cover?" and my mom gave me this strange look. I was like, "they are the main characters" while trying to hold back my stuttering. I know this is a light bl but, how am i supposed to bye all 10 volumes without my parents discovering that the manga is bl? and my sister reading my manga and discovering it's a bl? sh is younger than me and is very persuasive, so if she wants something, she goes straight to my parents telling them i am mean and not sharing my manga with her. oh my god this is going to be bad.