Instead of throwing up Oregon's signature two-handed "O" sign (see random fan in the background), Thomas put his index and pinky finger in the air to give Texas' "Hook'em Horns" sign.
Thomas is a Houston native and might have been giving a shoutout to his hometown. Or perhaps he really dislikes Baylor and was wishing Texas good luck in today's game against the Bears. Maybe he was taking Mike Pereia's advice a little too far. Whatever the case, if you can read American sign language, it's better than the alternative.