NEVER dangle a live rodent by tongs.. It's very inhumane and painful. Do you want to introduce a scared, hurting, and confused rodent to your snake that could easily get bit, or a calm and curious rodent to your snake? Calm and curious won't get your snakes bit.
I have some adult females who come out of their tubs a good 2 feet and I've given up trying to get a rodent into their tubs. I just hold the holding tub of mice up to their tub and let them pick their own. Works better for me and them. After they get a mouse, I can gently pick them up and put them back into their tubs and close them up.
To feed live properly, grasp the mouse gently but firmly at the base of the tail by the butt, drop into the enclosure on the opposite end of the snake, and leave it alone. These snakes have millions of years of evolution under their spurs and don't need our help.