Hard Daddy by Megan Michaels

Mace Cardelli is not the kind of man who stands by while a woman is in danger, so when he sees a mobster threatening an innocent college student he doesn’t hesitate to intervene. But gunning down a member of a mafia family won’t go unnoticed, and the girl will need his help, whether she wants it or not. If that means bringing her home with him and taking his belt to her bare bottom when she puts herself at risk with her reckless disregard for his instructions, then so be it.
Kyleigh Pizzulo isn’t sure what to make of the former Navy SEAL who saved her life and then insisted on keeping her under his protection, but there is no denying her helpless arousal when the battle-hardened brute spanks her until she is sobbing, and before long she is screaming her submission into the sheets as one brutal climax after another ravages her naked, quivering body.
Though she would never have imagined it possible to feel so roughly used and yet so deeply satisfied at the same time, it is only when Kyleigh is left bound and on display with her tears and his seed dripping down her face that she understands just how thoroughly and shamefully Mace plans to master her. But can this beast who makes her call him daddy keep his feisty girl safe?