applying static effect animation to model

chanidae

I'm trying to figure out how to apply a static animated effect to a model like if the character is holding a torch or a candle on a hat. the best example of this I found would be the flaming horns on this vtuber: https://www.youtube.com/watch?v=-ivkPJysBOk

so far I have not seen a single tutorial how this can be done with the keyframe parameters. it would even better if there's a way for the flame to maintain its vertical orientation regardless of the tilt of the model's head or hand and body.

I'm hoping I would get some assistance here, thank you in advance!