You shouldn't fracture someone else's finger.
Sean is an MMA fighter, and his opponent keeps sticking their finger in his mouth.
Sean wants his opponent to stop bothering him with his finger.
Sean tells the referee what his opponent's been doing, and the referee warns his opponent.
Sean bites down on his opponent's finger the next time he puts it in his mouth.
Sean's opponent leaves him alone, and Sean gets to continue the fight.
Sean's opponent is injured, and Sean is disqualified from the match.