Wicked Nights (Uniformly Hot! Book 53)

Winner takes it all…off 

Former diving champion Piper Clark never loses. Unfortunately, if she doesn't land this lucrative contract, her diving business will fail. Worse still, it will be at the hands of her childhood nemesis, Cal Brennan—six feet of hard, rugged former Navy SEAL. So Piper proposes a wager: whoever loses the diving contract must take orders from the winner…in bed. 

Cal needs this contract for his own reasons. A former rescue swimmer, he may be having a few issues with diving since his last mission ended, but Piper doesn't need to know that. Something about her impulsive nature makes Cal rise to the bait, and there's nothing he'd like more than to show Piper exactly what rules are good for. 

All bets are on. And someone's about to start playing dirty….