I hope I understood your question. Jacob first appeared in the RTS story "At the Mistress' Pleasure" as the mistress' first lover. Same woman here, just not named. He's a man in his later twenties. His girlfriend shrank him during sex as happened to most couples when the Rebalancing began. When she told Jacob she needed another lover, he recruited Brandon, a man about 20, who had played on a soccer team he coached. She went over to his house, gave his mother a used car for a dowry and took him home, then shrank him. He joined Jacob as a sort of apprentice lover/sextoy. They usually have sex with their mistress together, and often spend the night inside her. They work closely together and there really is a lot of mutual respect and no jealousy. Brandon ended up taking the mistress' backdoor virginity (see link below): 

Rebalancing the Sexes: At the Mistress' Pleasure by ltltb (giantessworld.net)