My sister touches her pussy in the library, it's not normal

What my sister does is not normal at all and I am the first to admit it, but she must spend so many hours studying that this must be how she disconnects a little, but of course, in a library where there are more people studying and in silence you can't start masturbating because that can be heard and also the security guards are watching you through the cameras, woman, but of course, who stops a girl who is really horny?