To get the mouth open I take the mouse's nose and put it on the front part of the mouth, then push a little. The open up very easily, and since I check for RI frequently they are used to opening up for me no problem. Well, anyway. The slanted nose acts like a crow bar and when in to past the eyes she bites down, hard. Then sits there and considers whether to eat it or not. I've only done it twice. But every time it takes 3-4 tries. She'll start to eat, but then decides she doesn't wanna after seeing me move.
I wish she fed like the runt. So easy to feed in snake bags.