we saw his dick while in merman form in the bath tub? where does he tuck it in? lol

If you're curious. A bunch of artists basically came up with the idea that mermaids have a pouch on their crotch area where their dick/vagina is hidden there. It also doubles as an asshole where it's sensitive like a vagina....so mermaid segs would be facing each other...you can find it in other mermaid BLs or simply googling lol. Just becareful cus you might get shark/dolphin/whale dick instead.