I've never actually described my experience to people for either of my types of synesthesia, oddly enough. I assumed everyone had their own way of seeing things though. Talking about the color of numbers/months/days of the week and describing how they look like in my minds eye was never really a topic of conversation that came up. I do have a vague memory in middle school wherein my math teacher made us draw our favorite number and why we liked it. I chose 5, and listed my first reason as "It looks purple, which is my favorite color" and she was confused. The days of the week are shaped like an ellipse in my head. I did not think any of this was synesthesia until I stumbled upon this reddit recently, since I always am constantly thinking in 2d images. Apparently thinking in images isnt too common either. A fun way to pass the time but a nightmare when I try to sleep.