"It's a warm evening, a good evening for a swim." The voice is deep and soft, and it takes you a moment to recognize where it was coming from. A man peers out of the water at the edge of the lake not far from you. There must be a deep pool where he is as you could only see him from the chest up. A strong, powerful chest, with broad shoulders and muscular arms that are folded on the bank. His blond hair is wavy, but hangs dark and damp to his shoulders, his eyes a bright green. He stares at you with a hint of amusement.
"Surely you want more than to just dip your feet for a while?" He brushes his hair back from his face with his hand. There's something strange about his hand but you can't quite put your finger on it. A few faint greenish blue lines can been seen on his neck, and he wears a necklace of shells and brightly colored stones.
You look around, unsure. "I don't know. It's getting a bit dark for swimming." But you find yourself moving closer to the stranger to get a better look at him, leaving your socks and shoes behind.
"Don't worry, I'll look after you." You kneel by the man as he looks into your eyes and suddenly he surges out of the water a couple of feet, his hand wrapping in your shirt as he pulls you in close. Warmth floods through you as your lips meet his, then you feel like you're being doused. No. Not doused. He's pulled you into the water. You try to struggle and thrash but he has both his strong arms wrapped about you now.
You panic, desperate for air, then realize, you aren't drowning. You feel an odd sensation at the side of your neck. You lift a hand and feel small slits in your skin. Gills?
The man finally breaks his kiss and separates from you. You feel like you should have trouble seeing through the night dark water but you don't. His upper body is the blond haired Adonis you saw above the water, but below his waist he's fish like, a long finned tail covered in blue-green scales with silver striping that shimmers even in the faint light that reaches into the water. You can also see around you, the lake being far deeper and larger than you thought from the surface. "Isn't that better?" He asks with a smile. His words still carrying through the water as easily as they did in the air.
"It feels... odd. What did you do?" You say. Moving your arms and legs to tread water, somehow maintaining your position under the surface instead of floating or sinking.
"Just a little magic, to let you see, breathe, and talk underwater." He smiles. "It's easier to swim without clothing." The merman is back on top of you, his fingers plucking at your shirt. You finally notice what's odd about his hands, there's webbing between those long, slender digits. You let him remove your shirt, which goes drifting off in an unseen current, probably to wash up on the lakeshore. His chest presses against yours as he takes another kiss. "It's been a while since I had a human to play with. My name's Titus by the way."
Sharing your name with him, you look down as Titus begins to unbutton your shorts. You gulp softly as you notice that right below where his human stomach fades to his fish half a slit has opened, exposing a long, girthy, and very human looking cock. No balls that you can see, but Titus is very much erect and eager.
You shorts are finally loosed and allowed to drift away. You can feel Titus's cock, hard and hot against yours, but he seems to be waiting on you for the moment.