What Defines Sexual Expression?

The term sexual expression gets used a fair bit in by people who work and advocate for better access to general health and human rights for people around the world. But what exactly does it mean? What does it mean to say that people have the right to sexual expression? Is being sexual the same as sexual expression?

One of the problems with all sexual definitions is that they are framed by other definitions. I'm sure there's a Latin word for this, but the only ones I can come up with at...