An idea prompted by this
thread on bisexual incest, but I didn't want to hijack it.
A twenty year old junior college student, still living at home with his widowed mother. He never knew his father, who died when he was a young child. He is also very shy around girls. He gets his jollies by raiding his mother's room and wearing her bras and panties, trying her makeup, etc., when she is not at home.
Of course one fine day she comes home early and catches him in the act. He is naturally mortified. But she is fine with it. She explains to him that his father was a died-in-the-wool cross-dresser, and that they used to make it part of their lovemaking experience. She was only hoping that he would inherit the fetish. Now that he has, she helps him with his makeup, his hair, his lingerie, and turns him into the perfect sissy for her lovemaking pleasure.