It is the fundamental problem of magical academia - how do you explain something when everyone experiences that thing differently? The Elves of Ulthuan use poetry, a language where every word has a dozen contradictory meanings, and a lifespan measured in centuries. The Colleges find the best results from a Master and Apprentice system, so that the teacher and the student end up with similar magical senses and a solid understanding of where they differ. But the drawback of that is that it makes widely disseminating information impossible and standardization close to it. So every Wizard who puts quill to parchment ends up turning to metaphor, and every recorded Magesight observation is described through the lens of a more mundane sense. Usually sight, sometimes sound, the more repugnant magics often as smell, and for you, the Waaagh is best described as the taste of metal in your mouth and the feeling of an unpleasant vibration in your bones.
But as fundamental a problem as it is, it's also one that your audience will be familiar with wrestling with. While you do have to filter your observations through metaphor, you don't have to worry about it misleading them the way you would with laymen. So you merely couch your metaphor with a few others from your library - the discordant tones of a Light Order observer, the sensation of half-welcome heat mixed with entirely unwelcome humidity of a Bright Order Battle Wizard, the staccato pulsations of a Runesmith. Those that have felt it for themselves should be able to translate to their own senses, and those that haven't will have to figure it out when they first do. You regret that your Magesight had apparently decided that Waaagh is a flavour, as if it was a sight you could replicate it with your MAPP.
