Hunter had intended to tell his sister they should go, or look away, or make any other number of good decisions, but when her body pressed back against him he couldn't think of anything but that feeling. The length of his cock was pressed up against her back, through his trousers, and Hunter nearly whimpered at the intense sensation. The wolf in his wanted to push her forward onto all fours, claiming her as his and only his.
It was only when a mix of the couple's voices travelled down the alleyway that Hunter realized he had let his eyes close. He opened them again to find the boy pressed up tight against the girl, thrusting up against her. It only took one deep scent of the air for Hunter to tell that he was inside her.