Write an erotic novel about a woman named NAME_1 who teaches a women's self defense class. Today NAME_2 is their practice target. NAME_1 directs the women to hit, kick, knee, and grab NAME_2's balls to inflict as much pain as possible. As they practice the techniques on NAME_2, the women become turned on due their control over NAME_2, undress him, and take his penis inside their wet pussies. The women ride him until they all climax and squirt and pee all over him and force him to climax multiple times, while controlling NAME_2 by kicking and grabbing his ball with an iron grip. They force him to ejaculate on his own face and pee on him as he is being rode and inflict great pain to his balls. The erotic novel should be at least 18 sentences and include many sexual details and use many erotic words such as penis, erect, wet, pussy, squirt, etc.