yES

Or when my mom is next to me and goes 'what are you reading'

Always

When I'm staring at my tumblr or twitter feed in public >.<

One word: boyxboy

me. even in my house alone.

At school reading things and someone has been behind you the whole time

Ever read a manga in public? That's even worse, it has pictures in it

There is something wrong with you if you get sexually excited from books, just sayin .-.