Congrats, I know the feeling. Its quite relieving once they eat.

Also, make sure youre getting the right sized prey for him. I usually try to feed as close to 10% of my snake's body weight as possible for my finicky eaters, because anything bigger and it scares them. Also, flicking the top of the mouse's head probably doesnt do much. In fact, some people have told me in the past to smack the rodent on the ground to "stun" them, but I always found that to be way too cruel and our snakes are killing machines in the wild, theres no need to stun their prey for them. Just stand by with a pencil or tongs to make sure you can restrain the mouse if it starts scratching or biting your snake, after your snake strikes and coils.