What do you think? Your sudden and massive erection makes it pretty clear what you think of it, although Katie doesn't notice that under the water.
"Ever since I was a kid, I've been into mermaids. They have always been a huge turn-on. I never mentioned it before because I though most people would think I was a freak. To find out that my girlfriend is a mermaid may be the best news of my life."
Katie smiles as the two of you drift closer in the water. You reach out and pull her into a deep kiss. Bringing your bodies together makes it clear to your girlfriend just how happy you are about her current form.
When your lips finally part...