The skit, which took place on Monday, involved the duo dropping tokens down a board to see which two ingredients they would be mixing together with Aviation American Gin.
The possible ingredients included the likes of Mountain Dew Slurpee, maple syrup, clam juice, bacon, egg and cheese, bone broth, melted ice cream, Twinkies, grape soda, horseradish, suntan smoothie, kombucha and blood.
Reynolds went first and landed on Twinkies and grape soda, which the actor found to be disgusting. "I would rather drink spinal fluid than drink that," he said.
Next up was Fallon who also landed on Twinkies along with horseradish. The combination made the late night host puke inside a garbage can.
Reynolds, for the finale, downed a glass of bone broth, bacon egg and cheese, blood and kombucha.
Reynolds also discussed making Deadpool 2 and how the home video release of the film will include 15 minutes of new footage and unused jokes not seen in the theatrical version.
"For us it's been a blast because we get to use all the jokes that we wished we could have kept for the main movie," Reynolds said before sharing his original idea for the Deadpool sequel.
"The whole story of the movie would be Deadpool trying to steal the big red chair from The Voice," he said.