My cali king had a tendency to get some cyprus in his mouth whenever he ate. My bp eats when i hold his dinner by the back of the neck and he strikes it only while im holding it with the tongs. I always do it above a flat rock he has in the tank. After that he sits on the rock to get the mouse down then USUALLY proceeds to his UTH to digest. I used to use a clay platter, like the ones that go under clay potted plants to catch excess water, to wiggle a mouse over so once he striked it he would sit on that and not eat substrate.