Beyond Oak Street by Emily Tilton

Though Tricia and Louisa now share an apartment in Manhattan with the billionaire brothers who purchased them from the Institute, their new daddies never hesitate to deal with them in the same shameful ways they remember from back on Oak Street, and they are reminded often that it is not up to them to decide when, where, and how their beautiful bodies are used and enjoyed.
But no matter how often Tricia is soundly spanked, her naughty behavior only seems to worsen. Will her daddy need to punish her cute little bottom in a much more intimate, embarrassing way?