A mermaid tail is a costume (usually made of swimsuit fabric, silicone or rubber) that can either be swimmable or just for show.
A mermaid tail allows you to look and feel like a mermaid by putting your feet into a fin covered by fabric to look just like the magical creature.
a mermaid tail is a tail of a mermaid, though some people (typically texans) refer to themselves as a mermaid tail or having possession of a mermaid tail. those with a mermaid tail, seem to be slightly or overly phsychotic.
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.