moltenmetal

@Override
public void onUpdate(ItemStack stack, World world, Entity entity, int itemSlot, boolean isSelected){
    if(!entity.isBurning() || !entity.isImmuneToFire()){ //No need to set the entity on fire if they are already on fire or are immune to fire
        if(entity instanceof EntityLivingBase){
            if (((EntityLivingBase)entity).getHeldItem(EnumHand.MAIN_HAND).getItem() instanceof Tongs || ((EntityLivingBase)entity).getHeldItem(EnumHand.OFF_HAND).getItem() instanceof Tongs){
                e.setFire(1);
            }
        }
    }
}