Step 1: Have a hot beverage ready (a “tall” is not enough!)
Step 2: Get two bags of ice.
Step 3: Run cold water into tub, and get in, fully dressed, with a big sweatshirt on top.
Step 4: Add ice, set timer for 15-18 minutes.
Step 5: Read or carefully play with smartphone (i.e., don’t drop it in the water!) to take your mind off the cold. Wiggle your toes and flex your feet from time to time to make sure they don’t freeze.