Beautiful Bastard Series by Christina Lauren

Beautiful Bastard (Beautiful Bastard #1)

An ambitious intern. A perfectionist executive. And a whole lot of name calling.
Whip-smart, hardworking, and on her way to an MBA, Chloe Mills has only one problem: her boss, Bennett Ryan. He's exacting, blunt, inconsiderate--and completely irresistible. A Beautiful Bastard.

Cocktail by Alice Clayton

Wallbanger (Cocktail #1)

The first night after Caroline moves into her fantastic new San Francisco apartment, she realizes she's gaining an intimate knowledge of her new neighbor's nocturnal adventures. Thanks to paper-thin walls and the guy's athletic prowess, she can hear not just his bed banging against the wall but the ecstatic response of what seems (as loud night after loud night goes by) like an endless parade of women.