A fantasy story involving a classical evil dragon, not a furry or monsterboy etc.

He gets off on brutalizing the maidens sacrificed to him, sadistically toying with them psychologically as well as their small, frail, bodies even using his monstrous penis at times.

End should involve the dragon himself meeting his own gruesome end somehow at long last, penile destruction encouraged.

Gore detail is encouraged to be as high and gruesome as you like.