March Growth by Jenny Plumb

Marilyn has hated herself for being kinky since puberty, and she avoids thinking about it as much as possible by throwing herself into her schoolwork. Over the years, she has come up with several methods of punishing herself for the kinky thoughts that go through her head, because she believes they are sinful. As an introvert hiding a shameful secret, Marilyn spends most of her days studying accounting in her dorm room instead of socializing. All of that changes when Marilyn’s mother cajoles her into doing some volunteer work with the student Christian group on campus, where she meets Ford.
Ford, the volunteer coordinator for the Christian group, is friendly and outgoing, and Marilyn is shocked when he expresses interest in her. They get to know each other during their volunteer work, and Marilyn finds herself attracted to Ford’s natural dominance. But having a dominant boyfriend only brings her kinky thoughts to the surface, and then those thoughts make her want to punish herself more often.
Will Marilyn be able to keep her shameful secrets from Ford? And if she can’t keep her secrets, will she lose him forever if he finds out?