Kaden's Colors by Ryan Loveless
The first alien immigrants arrived on Earth long before Henry Mekes was born. Now they’re policed by the government, forbidden from attending school, and assigned menial jobs to prevent them from becoming drains on human society. Twenty-two-year-old Kaden, for example, was assigned the job of sex worker.
When eighteen-year-old Henry and his friend Ellil meet Kaden in a grotty backroom to avail themselves of his services, alien rights are the furthest thing from their minds. It’s not until afterward, when Henry is trying to remind himself aliens can’t get enough of sex, that he questions his actions and the rules of the world he lives in.
Something about Kaden compels Henry to return again and again—but only as a friend. Soon he and his classmates hatch a plan to free Kaden, but even if they succeed, the world is still full of prejudice against aliens—and those who love them.