Lawrence is captured, made to clean himself thoroughly and brought to the Bey's room. When he resists the Bey's advances, the Bey tells his corporal to take Lawrence out and "teach him everything."

Then they beat and whip him brutally as well as "play unspeakably" with him and in the end he also mentions that "my integrity had been irrevocably lost."

So while he may not have been sodomized, it's difficult to come to any other conclusion than that he was in some way sexually assaulted or molested.