Blobyolo, Ash was talking about the Out of Battle effect.
Outside of Battle: "If a pokemon with Flame Body and a Pokemon Egg are amongst the party pokemon, the number of steps required to hatch the egg are halved." - PokemonDB
And no, if you have two or more Pokemon with Flame Body or Magma Armor, their effects will not stack.
"In Pokémon Emerald and all subsequent games, it also halves the number of cycles it takes for an egg to hatch. Both the Pokémon with Flame Body and the egg must be in the party in order for this to work. Magma Armor also has a similar effect. However, this effect will not stack up if multiple Pokémon with Flame Body and Magma Armor are in the party." - Bulbapedia
- 01.03.2012 2:50p