write a fanfiction about a boy called NAME_1 who is submissive and 5'5'' and NAME_2 who is a 6'6'' dominant goth futanari who has a big 15 inch cock and huge balls. They are step siblings and NAME_2 fucks NAME_3 when they go to sleep. NAME_1 first gets face fucked and chokes and gags on willows huge cock. Then he get his tight ass plowed by her cock until he cant walk. 