Logan Woods & Steam Books 
Double the Phallus, Double the Pleasure — A Sexy Supernatural Erotic Short Story from Steam Books [EPUB ebook] 

Join Jivan, an ancient Incubus performing his duty to impregnate mortal women, as he seduces college girl Faith and her roommate, and then completes his mission by joining his Succubus friends Sevana and her apprentice, Anush. Jivan is always up to the task—it helps that he has two penises. WARNING: This 4, 201-word story is a steamy read that features explicit sexual content and may be too much for some readers to handle!