From GameWatcher: “Your Fallout 76 journey will inevitably take you through The Savage Divide and to the Top of the World. There, on the third floor. youll find Rose, a modified Miss Nanny that gives you the Flavors of Mayhem quest which tasks you with testing some of Roses weapons on the local wildlife.
After youve tested Roses Syringer on a Yao Guai, shell ask that you take her Explosive Bait through a similar process.”
Source: N4G PC Fallout 76 – How To Craft Explosive Bait?