'Naked & Afraid' Contestant Burns Penis On Hot Coals, Captured on Video

Turns out there is something worse than being dropped into one of Earth's most extreme environments with no food, clothes or water -- and it involves a survivalist's penis and an open flame!!!

The painful crisis unfolds on the upcoming season premiere of Discovery's "Naked And Afraid" ... when hot coal pops from a fire -- set for heat and survival -- and lands on the tip of UK contestant Sam Mouzer's penis, which he refers to as his "little soldier's helmet."

TMZ has video of the indecent incident ... Sam and fellow contestant, Lilly, are sleeping naked next to the flame when Sam suddenly screams out in pain. Talk about unfriendly fire.

While Sam worries his little soldier is going to look like it got blasted with buckshot after spending 21 days in America's Wild West, medics were on hand to provide some pain relief.

Check out the clip ... Sam's somehow able to keep a sense of humor as the medical staff did their thing down below.

Laughter really must be the best medicine, 'cause we can't figure out how he managed a smile.

The new season premieres Sunday and Discovery tells us Sam and Lilly are put through the wringer during 3 weeks in New Mexico ... where they get blasted with snake poop, deal with plummeting temperatures and are stung by scorpions.

Something tells us Sam, and his scorched tip, had the worst experience. 🔥