[He moved slowly, careful to show he meant no harm. He cut a few holes in the sheet, forming it into a make-shift poncho of sorts, that draped over her head and trial over most of her body and tail. He shortened up the end to make sure too much didn't trail behind her.]

Just push your arms through these holes. I don't know if mermaids need to stay moist, but if you soak this it'll keep you wet longer.

[He sat down besides her when he was finished, trying to think up something else.]

Well, it's functional, but not very flattering attire. What you need is some sort of fish-tank on wheels, or something.