I feed a few of my snakes two mice, but not at once. When I thaw them out, I always take the one out to feed a certain snake, so the other mouse that's thawing does not get cold by the time my snake is done with the first one. I feed both of my BPs, Monty and Candice, two mice and I also feed my Corn and one of my King snakes two mice. If you wanted to feed your snake two, here is how I do it:
Thaw out all f/t mice until they are warm. Take one mouse out of the warm water, dry it off a bit with a paper towel, and offer to snake. I also will take out more than one mouse, but that's because I feed the other mice to each snake. I wait until one of the snakes are done, then I take out another mouse that's thawed out, dry it off a bit, then offer to the snake.

That's how I do it, just so the second mouse doesn't get cold by the time one of the snakes are finished with the first one I offered.