I hang it on the side of the sink/vanity. In my case the side by the toilet.
Linda C

In this bath it hangs below the switches.

I meant to say the outlets are on the left and the toilet on the right. there is not room to hang below because the towel will hit the counter.

Is there any room to the left of the mirror or does it take up the whole space?

Do you have a pic you could share? Might help.

No pic yet, but to the left of the mirror is the space above the toilet. It is a very small bathroom. When you walk in the vanity and toilet are on the left and tub on the right.