Answer:
Looks like water, but it's heat. Sits on sand, lays on concrete. A play on the eyes, but it's all lies.
Gets rid of bad ones, short and tall. Tightens when used, one size fits all.
All about, but cannot be seen, Can be captured, cannot be held, No throat, but can be heard.
A leathery snake, with a stinging bite. I'll stay coiled up, unless I must fight.
I go around in circles, but always straight ahead. Never complain, no matter where I am led.
What language does a billboard speak?