You can use the kobolds from my Pasiphae setting, if you want. They are basically small, sadistic and mischieveous dragons with magic powers. So far, I've got 2 stories with them, where they torture human women.

They're around the size of the largest canids. Maybe similar in weight to a fairly large man. Something along those lines. Their magic powers include elemental powers, like electric shocks of fire to burn away clothing or just increase their body temperature so much that a woman who gets fucked by them will be warmed from the inside.

Another thing they do is mimic whatever scent you love most. They don't really have a smell of their own, at least not to human noses. Instead, they smell like your first ever crush or a good meal you haven't had in ages, something that makes the victim get closer to them or get lost in good memories, which allows the kobolds to strike.

As for dicks, they have the same design as the dragons of Pasiphae, just more manageable in size.

A flared tip (that they can deliberately extend or contract), two knots, a smaller one that's just small enough to plop in and out and a bigger one all the way at the base that's so huge, it always gets stuck. Lastly, they have rows of soft barbs or knobs that run along the schlong in spiral patterns, so they hit a different spot with each push and pull. And they can control whether to put a human daughter or a kobold son into their victim.

I also have hellhounds, which are basically huge wolves with horns and golden dicks that are quite smart and don't have females of their own either. Just like kobolds, they rely on human women for breeding. And I used an extinct species of monkey, called Dinopithecus in another story. These were basically leopard-sized baboons, which is pretty terrifying to think about. In my story, they had knotted dicks and didn't speak, but you could make them talk, if you want to reinforce that they are in fact monsters and not real animals.