David Blaine does this trick with water and kerosene. He drinks about a gallon of water, then swallows some kerosene, which he spits out to do a bit of fire-breathing. Once his target is lit, he goes into firehose mode and extinguishes it with the water. It's marvelous to see in person, but getting it just right took a YouTube video of a security guard in Liberia and five years of searching.
As Blaine explained to a rapt audience at Genii Convention 2017, he'd been trying to make the trick work for some time, but couldn't master the amount of force it took to expel the water hard enough to put out the fire. He then stumbled across a YouTube video that perhaps held the answer: a man shooting water of his mouth with such strength "it looked like a hose was behind his head."
Blaine got in touch with the missionary who recorded the video to ask him if it was legit and was told that, yes, it was genuine. He then began searching for the star of the clip, and finally tracked him down five years later. But the man's talent came about by necessity, rather than a desire to entertain. People in his town were only allowed to carry two buckets of water a day from the local well; he learned how to carry a full bucketful in his stomach, then bring it back up when he got home. He shared his secret with Blaine, who uses it for more entertaining purposes.
That saga is just one small detail of the time and research Blaine put into the fire-breathing stunt, but as the audience at Genii Convention learned, it's pretty typical for a trick he puts his mind to mastering.