Reverse Trap. She’s a girl, and she’s like 12.
He marries the titty elf and the flat cat, but IIRC, they didn’t fug, just lick and touch. Because he didn’t get off, he goes to the capital for a monster girl massage parlor service and later, almost buys a prostitute. That’s as far as I got.
IIRC, he gets more paizuri/BJs from people outside his immediate harem.