Before you put the costume back, you remember that some of the performers you've heard about are mermen rather than mermaids. You wonder what it would be like to wear a mer-tail yourself. You're all alone at home. Your girlfriend will never find out, right?
You decide to give a try. Laying the tail on the bed again, you strip off your clothes and get on the bed. Carefully you slip the tail over your legs. It's snug, but comfortable. You pull it up slowly, not wanting to possible damage it, especially if the costume is too small for you. Fortunately the costume seems a little stretchy and you slip into it until your feet find a space at the bottom. With a little tug, the costume comes up to your waist. The snugness of the tail gives you a warm and pleasant feeling and your legs tingle a little. You kick your heels a little and watch the tail fin move. You ran your hands up and down the tail and the feeling is incredibly pleasurable. You quite enjoy being a merman and once again thing about your girlfriend as a mermaid.
You're very turned on and can feel your erection straining against the tail.