The rest of the day had gone as one might expect. Biff went through his daily routine (it never occurred to him that he should go home and change his underwear) with people laughing at him behind his back. The panties kept riding up, showing above his pants, reminding people of his predicament.
By the end of his last class, Biff was pretty upset. Sure, people weren't making fun of him to his face (he was still the captain of the football team), but he knew they were certainly making fun of him nonetheless. Some guys would have shrunk from the ridicule. Some even might have cried. Biff, however, reacted differently. Each twitter of laughter he caught, each giggle he could make out, fuelled his growing anger. He had nobody particular to be angry at, but angry he was.
After his last class was done and he stomped out to the parking lot to his car, he made sure to shove every freshman he could see into their locker, trip every nerd he came across, and he even punched one kid for looking at him too long.
Reaching his car, and feeling a bit better (from venting), Biff was glad that the day was over. He headed home.