How can my dragons use their tongues to control their fire breathing?

Question

Some background you may or may not skip

I was daydreaming the other day about how tamed dragons whose magic was somehow harnessed as an energy source by humans could be used as a metaphor for nuclear power in modern societies. While considering this, I surprised myself thinking "of course they would need to cut the tongue out of tamed dragons so that dragons can't orient their fire anymore". Don't ask me where I got the notion that dragons need their tongue for that. Still, this got me wondering about what conditions were needed for this thought to be true.

Background you should not skip

In my world, dragons ...

• ... fit the stereotypes defined in this somewhat related question
• ... breathe fire in the way described there except they use magic to conjure the initial flame, inside their mouth. The rest is similar: the liquid fuel is "sprayed" from a reservoir towards the flame, ignites and finally breathing is used to expel the burning fuel. It so happens that this is more efficient than using pure magic to conjure a full stream of fire.⁽¹⁾
• ... use their tongue to control the direction of the fire they breathe. This constitutes a competitive advantage over their ancestors who had to rotate their heads to do so: (1) the breathing direction can be adjusted to a moving target more rapidly⁽²⁾ and unpredictably, (2) the head can remain parallel to flight direction for better aerodynamics.

Question

If this is possible, what sort of motion / positioning of their tongue could my dragons use to control the direction of their breathing so that the flame is directed? This might be used in combination with other actions that control breathing, much like whistling. All I need is that the tongue be important enough that if the tongue is cut, dragons loose this ability and fall back on the original approach of turning their heads all the way.

An ideal positive answer would

• explain the mechanism,
• if possible back up its claim with examples in real-world fauna achieving similar purposes,
• not make use of any more magic.

An ideal negative answer would either demonstrate that this is not possible or that a significantly simpler mechanism allows dragons to orient their fire and would lead to the same competitive advantages.

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⁽¹⁾: magic consumes mana, which is hard to store and fluctuating. Fuel is a more secure way of storing energy for dragons.

⁽²⁾: please consider that tongue motion of reptiles is faster that that of humans, and snakes can flick their tongue back and forth at around 15 Hz

Answer 1

I recognise that this is based upon human rather than reptilian tongues, so may not be what you’re looking for, but perhaps your dragons could use their tongues as funnels to direct their flame. Not all humans can roll their tongues (though it’s not actually a genetic predisposition, apparently), but if your dragons are able to gain mastery of their tongues to curl the outer edges into a tube, they could theoretically use that to direct a focused jet of flame, rather than needing to swing their heads to blow a more dispersed cloud of flame.

Also, less of a directional thing than a variation in fire breathing style: musicians who play wind instruments are sometimes directed to make use of a technique called flutter-tonguing. Given that reptiles can move their tongues at a greater speed than humans, I wonder if your dragons can make use of this technique to more precisely control the flow of air, peppering their enemies with a barrage of fiery ‘bullets’, rather than just a barrage of flame. (And at the very least, it might just make them awesome clarinet players.)

Answer 2

They don't have to direct the fire, they just have to direct the spray of the fuel. Assuming the fuel is ejected out of glands beneath their tongues; moving their tongue will twist, compress, and distort their fuel glands to direct their flames. Not entirely unlike the process of gleeking that we humans are capable of.

Answer 3

What if their tongues got hot?

They wave their tongues to keep the gas stream ignited. Gotta mix it right for further reach, higher heat, sustained, fireball, etc.

You can use this as flair, with very well trained dragons able to fully burn the gas, and novices may leave behind small pocket that just smell foul when unburned

Answer 4

If the ignition happens outside of the mouth, you can establish that the spray from the glands is somewhat irregular and that the tongue is necessary to channel it outside. It would be similar to spitting. Without the tongue the dragons would splash themselfs and set on fire.

Answer 5

a significantly simpler mechanism allows dragons to orient their fire

Searching online, it seems that many dragons have side-facing nostrils.

In the same way that dogs can direct their ears independently, https://youtu.be/fsZK4yvKt-o?t=35 , it is reasonable to suppose that dragons could move their nostrils. https://youtu.be/zACUtVjcLBc?t=7

I suggest that they can selectively blow fire through their mouth or either nostril at will.

Answer 6

Muscle Directing

If you want dragons to control their aim with their tongues, then you would simply need them to use the muscles in their tongues to shape the route of the fires fuel to be whatever they need it to be. Its kind of like dumping a bucket of water versus using a hose. the dragon could shape ts tongue to be flat and simply bathe it opponents in loose flames, or it could narrow it to a narrow tunnel, like forming your own tongue into one, and using that to shoot a powerful jet of condensed flames at a smaller target.