Certain plant-based ingredients contain compounds that make your mouth feel numb or buzzy when you eat them.
Sichuan (or Szechuan) pepper husks contain a compound called sanshool thay "makes it feel like there's a continuous tactile stimulation while you're eating it, which accounts for that buzzing sensation many people report," according to Dennis Lee's article in The Takeout.
There's also cloves, which contain a nartural anesthetic called eugenol, which is why some people use clove oil for a toothache (and why clove cigarettes are such smooth smokes).
The author also describes his experience with a small yellow flower called a buzz button, which contains spilanthol:
A long time ago I had the opportunity to try an ingredient called a buzz button during a fine dining meal. It was a small yellow flower bud perched on top of the dish, and after I chewed it up (it had a grassy, herbaceous flavor), my entire mouth felt like it was being electrified with one continuous shock. I'd never had anything like it.
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Due to its numbing properties, spilanthol has been used for toothaches. It's extracted from buzz buttons and turned into a concentrate called jambu oleoresin, which is used for flavoring and for therapeutic purposes. The National Collaborating Centre for Environmental Health of Canada has a pretty interesting paper on buzz buttons covering its uses.
