If you add fuel to the fire, you do something to make a problem or an argument worse.
Isabel was upset about her new haircut. I said it made her look like her mum, but that just added fuel to the fire and she cried even more.
Don't shout at children if they're crying, it just adds fuel to the fire.
David has had a written warning from his boss about his behaviour at work, so he's going to complain to HR. I think that's a bad idea - it will just add fuel to the fire.
If you are fired up about something, you are really enthusiastic about it.
I'm really fired up about the big game tonight!
The 'Burning of the Clavie' is a fire festival which takes place in Burghead, Scotland, to celebrate the New Year. A 'clavie' is half of a barrel, which has been filled with tar and wood.