If I have time I usually defrost in the morning on the evening of feeding by putting frozen rat from freezer to refrigerator in some plastic bag. If not warm tap water no boiling or so for a half an hour or an hour. The rest of the process remains the same.

After day at work in the evening few hours before feeding I move the rat from fridge under the lamp of terrarium on the vent holes. I distance the lamp just right so the rat doesn't get warmer than 37-38C (~100F) and the snake can smell it's prey hour or two before feeding. That seems it also stimulates and prepares him for eating. He barely comes out of his hide and just waits for the food