Cocktail sauce is the standard condiment for all seafood. A very basic recipe but I found I needed to add it to my site to go along with my Frogmore Stew recipe.
Ketchup (about a quarter of a bottle)
Horseradish Sauce (found in the refrigerated section of the grocery store usually near the cheese. 2-4 Tablespoons)
Worchester Sauce (1 teaspoon)
Lemon Juice (1 teaspoon)
Now this is a very subjective recipe in that many people like their sauce different ways. I personally like a hot/spicy version. This is all controlled by the amount of horseradish sauce.
Take a small salad bowl and fill half way with your ketchup. Now take 2 table spoons of horseradish sauce and mix in the ketchup. Add one tea spoon of Worchester sauce and a about the same of lemon juice. Stir and serve. Add more or less horseradish for desired heat. I probably would use 3-4 table spoons in a small bowl.
Also, try and make this 20 minutes before serving and let stand at room temperature. This seems to make the taste more bold. Do not refrigerate the sauce as the cold sauce is not good on your seafood.