Not sure about using soft serve. Back when I grew up in CO and he hunted bear over bait I found old cooking oil and bacon grease poured on a rotting stump worked best. It would soak down into the wood and last a long time. Scatter pieces of old pastry around for them to find and snack on. But we had too many fools from CA move into CO and they outlawed spring bear hunting, hunting bear over bait and hunting bear with dogs and then they tossed outlawing trapping onto the same bill.