In the so-called Facebook 'fire challenge', flammable liquid is poured over the body and lit. The person then has to dive into a pool before the flames take hold.
Tyler O' Connor, nine, and his 11-year-old brother Shaun escaped serious injury after trying to take part in the 'Fire Challenge', Mail Online reported.
Footage of youngsters taking part has spread across the internet, with the videos being shared widely across Facebook and YouTube.
The boys' parents Donna O'Connor and Anthony Mummery, from Churchdown, Gloucestershire, have now warned others about the risk after their children attempted the stunt twice during one weekend in November.
"I felt sick and worried when I heard what they'd done. It could easily have been a phone call saying my sons are in hospital or they've died. They have been punished more than I have ever punished them before. It's shocking that kids are able to watch videos like that," a shocked Mummery was quoted as saying.
Parents are issuing warnings as the popularity of the craze leads to more and more youngsters taking part. London fire department officials too have warned against the inherent dangers of such stunts with fire.
"This is a stupid and dangerous craze. You're almost certain to seriously injure yourself and fire can easily spread to furniture and other flammable household items which is a risk to others," a fire department official was quoted as saying by the Mail.
Although Facebook has reportedly taken down two of the videos, many others are still accessible on YouTube.