Hotline Murmur inc., book 1.

Zack never intended to become a phone sex operator, but with half a college degree and a smart mouth, his options were limited. It helps that he has a knack for thinking on his feet and a willingness to roll with whatever his clients throw at him. Sure, he gets his fair share of creeps and unconventional requests, but it pays the bills, and he's in no danger of breaking his one rule: never fall for a client. Until a man named "John" starts call...