SF Worlds Series by Elle Thorne

Shifter Cy's sister is missing. He shouldn't be crossing into Tiero Territory to look for her. He should follow proper channels and notify the Tiero Tribe. But he can't. He doesn't have the time to wait around for niceties and permissions. Until he's caught. Damn the luck. It doesn't help that one of his captors is a beautiful curvy tigress named Lila. He needs to escape to find his sister, but he hates the thought of leaving the stunning bootilicous tigress behind.