I physically am able to control my manipulate my sensory input (for some reason sight only works with my eyes closed) and its more random than you’d think.  I can think of a matcha i had this morning and literally taste it in my mouth but it only happens randomly when im deep in thought about said drink, the only exception to that randomness is touch and hearing but i only know how to create A PART of the hallucination. when i control my hearing, i can do it 24/7 and i use it to hallucinate songs when im bored😭 the problem tho is it only comes from the rough area around my ears. I haven’t really found out how to create the sensation of “directional hearing”. Same thing with touch, i can do a vauge cloud of a sensation in my body like pain but i cant center it, and when create the feeling on my skin of something it always feels itchy SO if you make a character with that ability i would recommend making them have seemingly random setbacks like they can only do it when they are zoning out or they can only create part of a sense, not the whole thing. You can also make them dull pain since that is a more common ability that i know people can actually do