A tall, imposing rabbi with a black goatee who served as assistant principal and principal during his 27 years at Yeshiva University High School for Boys, George B. Finkelstein was the face of authority to Mordechai Twersky, who graduated in 1981.

So when Rabbi Finkelstein asked Mr. Twersky to “hit him hard” during a meeting in his office in 1980, Mr. Twersky said in an interview on Thursday, he was mortified. When Mr. Twersky refused, the rabbi knocked him to the ground and sat on him, goading him to wrestle. He could feel the rabbi’s erection, Mr. Twersky, now 48, said.

Mr. Twersky’s account was published Thursday on the Web site of The Jewish Daily Forward, which also reported that another former student said that in the same year, when he was 16, the Talmud teacher, Rabbi Macy Gordon, visited him in his dormitory room. Rabbi Gordon inspected his genitalia, the student told The Forward. Then he sodomized him with a toothbrush.

Both rabbis have denied engaging in any inappropriate sexual behavior.

Rabbi Gordon’s accuser said his parents had complained to administrators, who promised action but did nothing. Several years later, Mr. Twersky, who said he wrestled with Rabbi Finkelstein twice more, also raised concerns with administrators, and several other students also complained about the rabbi’s wrestling. Yet administrators of Yeshiva University, the prestigious Modern Orthodox institution in Washington Heights that runs the high school, allowed each man to simply leave.