I learned this at a much younger age thanks to my step father and mother. Though it never really set in or was actioned on until much later in my 20s when I was out of their reach/strings.

THe one or two times a year i go, i just say “That one” and point or touch the bottom of the cup.

for me, i always put my work bag in the back seat for this reason. I would have to open the back door to get it out. Never happened but it was a concern and i completely have a tendancy to be on autopilot in the mornings.