Pledge Slave by Evangeline Anderson

Andrew Baines is a new member of Alpha Psi, a reluctant pledge to the college's most popular fraternity. On the last night of Hell Week, Andrew completes his initiation with a carnal act designed to humiliate him. But instead of disgusting him, the deeply erotic encounter arouses him almost unbearably. Andrew is confused and tortured by his reaction. He doesn't want to think about the terrible urges he keeps buried inside, let alone act on them...urges that will get him kicked out of the fraternity and disowned by his family.
Tony Ginelli is an Alpha Psi brother, the recipient of Andrew's act of erotic initiation. When Andrew becomes his slave for the next two semesters, Tony masters the handsome pledge in every way that counts. As Tony discovers Andrew's long-held secrets and desires, the lovers forge a bond that lasts beyond college. But while Tony helps Andrew face his demons, he is terrified to reveal his own dark secret...one that could kill the very man he loves.