Add 2 (16-ounce) packages cocktail sausages to the bottom of a 4, 6, or 7-quart slow cooker.: When you nestle the cocktail sausages into the slow cooker, you will notice a compact, slightly shiny surface that is cool to the touch. The visual cue is the even layering of links across the base, not piled so high that heat circulation is blocked. The why here is simple, even exposure to gentle heat allows the sausages to warm through evenly and soak up sauce without splitting. You should hear almost nothing at this point, just the quiet hum of the cooker when it turns on, and the aroma will be minimal until the sauce starts to mingle. A common mistake is overcrowding, which leads to uneven heating and some links staying cooler in the center. Avoid that by using the cooker sizes suggested, and if needed divide into two smaller batches. Also, pat the links dry if they are extra slick from packaging liquid, so the sauce adheres better.
Combine 1 1/2 cup barbecue sauce, 1/2 cup ketchup, 1/4 cup brown sugar, 1 tablespoon Worcestershire sauce, 1 teaspoon garlic powder, and 1/4 teaspoon paprika in a medium bowl to make the sauce.: As you whisk these components together you will notice the sauce transform from separate elements into a glossy, homogenous mixture. The aroma will lift immediately, sweet and slightly tangy, with the molasses note from the brown sugar and the umami whisper from the Worcestershire sauce . The texture should be thick enough to coat the back of a spoon, which matters because a thicker sauce clings to each cocktail sausage and reduces watery pooling in the cooker. The reason this mixing step matters is to ensure the seasoning is distributed evenly so every bite tastes consistent. Stir until smooth and taste for balance; if a note feels weak, adjust a tiny bit. One trap to watch for is adding too much sweetener which can make the sauce overly sticky and mask savory tones. If that happens, a drop more ketchup can add acidity to balance sweetness. Use a medium bowl so you can whisk energetically and incorporate air for a lighter finish.
Pour the sauce over the smokies and cook on LOW for 2-3 hours.: When you pour the sauce it will sluice over the arranged links, coating them in a ribbon of glossy color that immediately begins to cling. As the cooker warms on low, you will start to notice a soft bubbling at the edges after some time, and the aroma will deepen into a rich, tangy perfume that fills the room. Cooking on low allows the sauce to reduce gently, thickening without burning, and gives the cocktail sausages time to absorb flavors without becoming dry or tough. Stir gently once midway if you can, nudging the links so sauce contacts all surfaces; this improves uniformity of coating. A frequent error is switching to high heat to hurry the process which can make the sauce thin and cause the sugars to burn, creating bitter notes. Patience here produces a sticky, clingy finish where each piece is glossy and lacquered. When finished, the visual cue is a thickened sauce that barely moves when the cooker is nudged, and the scent will be a meld of sweet and savory that invites immediate serving.