It's fairly easy. I bought a dozen minnows and then froze them in a ziploc. When I am ready to feed the baby water snakes, I thaw one minnow at room temperature along with the required number of pinkies (9 in this case, lol) I casually rub each pink's head on the sides of the thawed minnow. I then dangle the pink in front of a baby snake. They usually attack it eagerly. After a few times, most of the snakes will go for the pink regardless of whether it is scented or not. I think the fish scent just helps them to 'hold on' and swallow the first few times.
Takes only a few seconds.. and you can see the results, ;)