Bonding Games by Cathryn Fox

Former Navy SEAL Josh Steele gets tasked with a babysitting mission—watch over his boss’s daughter—a job he can only describe as hell. But when his assignment takes him to a tropical island, and he begins to see another side of Holly Fairfax, attraction sizzles between them—but he knows better than to risk his job for it.

Holly can’t believe that underneath those baggy clothes tech-guru Josh Steele is all ripped abs and sexy hotness. Ignoring said hotness is tough, especially since she has to work with him on the team-building exercises her boss has assigned if she wants a coveted promotion. It’s even harder when she discovers being around Josh brings out her naughty side – one she didn’t know she had.

But if she cracks the code on his cover, everything they’ve built could come crashing down.