In a project of mine, some people can bond with dragons. Now, I want there to be a mental link, but I do not want it to be too... clear? Maybe anthropomorphic is a more accurate term. My dragons are wild, willful beasts, and they are not easy to tame. They don’t talk, and their thoughts are all about fighting, food and... well, let’s keep it PG-13. They’re not human to any real degree, at least not more so than a snake. Basically, I want to strike a balance between a feral intelligence and a wild reptile. The dragon riders understand more about their beasts than normal people, but they don’t know everything. How should I go about this?
In my limited experience, this sort of balance can only be achieved by writing, writing, writing. You have to write it out from your heart, write multiple scenes. Be frank in one, coy in another. Read them out loud. Eventually you will know when you've hit the right balance, and you can revise accordingly. - MC
I'd advise writing it and posting the work up for critique. General advise won't help you as much as getting detailed feedback. What @montecarlo said: Write, write, write.
Only you will know what the perfect balance looks like for your story. Reading this, it reminded me of falconers building relationships with their falcons; maybe that's something you'd be interested in researching. They're not reptiles, but the birds are intelligent and wild, and they get treated as such.
What you're describing is more a Wyrm than a dragon. Dragons are traditionally superior beings and extremely intelligent. Eastern cultures have dragons primarily being benevolent creatures. Wyverns are a subspecies of dragons that are less intelligent, yet still smart enough. The serpent like quality and very primitive mindset would be a Wyrm. Wyrms look like a snake with a dragon's head and a dragon-esc set of wings. As for the bonding, rather than tangible words and conversations, why not have it set to be a mutual emotional bond. The mount feels and is influenced by the rider's emotional state, and vice versa. This would create an equal bond with both good and bad effects. You could then have riders traditionally condition their minds to better control their emotions for better unity with the mount. Food for though.
Just an idea, but personally my approach to describing a mental link between human and dragon would be creating a visionary image and metaphoric state. Perhaps you could allow visual setting and verbal and physical methods of communication fall to the wayside during this mental link and instead describe images your dragon’s see “mentally” as a form of communication which they project to your character. If they want to convey friendship, instead of saying “you’re a great friend,” they convey a mental image of a human rubbing a dragon’s snout while the dragon reacts positively. The dragon is communicating friendship but not with words. It could go both ways, the dragon can’t understand human words or word-based telepathy in the mental link, so the human has to construct a mental image (or emotion, as suggested above) to “push” to the dragon. This could be done with scenarios/mental images, or if you want to get more complex, less literal metaphors of some type.
Have you read Anne McCaffrey's Dragonriders of Pern series? The first three books are the core trilogy -- and, at one time, were available as a 3-book set. In her books, each rider bonded with and had a telephathic link with just one dragon (except for a very few special people who could communicate with all the dragons). But her dragons weren't as wild as yours apparently are going to be. Your dragons might be closer to McCaffrey's fire lizards. People finally learn that they can "impress" (bond with) fire lizards, too, but the fire lizards function on a much more basic level than the large dragons (which are the result of genetic manipulation). The Menolly trilogy (parts of the Dragonriders series) would give you the best window into the fire lizards.
