In the underground world of Cockfighting, Jess is the term used for "odds".
A wagerer would yell "Jess!! Jess!!" which means he's going for the favorite. He would wager $20.00 to win, $25.00 if he loses. On the other hand, a wagerer yelling "Take Jess!! Take Jess!!", is going for the underdog. His $20.00 would turn to $25.00 if the underdog wins. Similar to 6-5 wagering.