A vampire Whumper who tests out flavors of blood by feeding and injecting their Whumpee with different things.
Pros: maybe delicious foods
Cons: asbestos, radium, arsenic, carcinogens, etc.. plus, ya know, being a blood factory for a vampire
When Whumper wants to feel something, they give their Whumpee drugs. Could be hard drugs or Benadryl on high-pollen days.