Your girlfriend has a mermaid tail costume. You vaguely remember her expressing an interest in mermaids at some point, although you suppose most girls think Ariel is pretty cool.
Laying the costume on your bed, you get a better look at it. It reminds you of costumes you have occasionally seen on the internet - news stories of people wearing realistic mermaid tails for swimming, at festivals and tourist attractions, and in movies. The costume appears to end at the wearer's waist, with shiny scales and a broad tail fin. It would probably be fun to swim in a tail like this. You run your hands down the material.
You imagine your girlfriend laying on the bed wearing only the tail and are immediately turned on. You run your hands down the material and out to the tips of the fins, imagining the day when you'll see her in it. You wish she was here right now.
Unfortunately, as far as you know she's still at work. You pick up the tail holding it in front of you. Better put it back where you found it.