Stir together crab meat, cream cheese, milk, Worcestershire sauce, horseradish, mayo, and green onion in the bottom of a slow cooker. Cook on high for 30 minutes.
Remove lid and stir well to incorporate all ingredients.
Sprinkle shredded cheese over top. Put lid back on and cook just until cheese is melted, about 5 minutes.
Remove lid and stir again. Switch to low or "keep warm" setting. Serve with crackers and various veggie dippers as desired.