I'm a mechanical engineer, and I often have to do a double thumbs up with my hands like b_d. It's the only way I can remember what comes first in the alphabet. In danish you spell boat båd, and if you mess up the order the b and d will be on the outside of the boat and drown, like dåb. Still works 20 years later
Do you have dyslexia or something like that by chance? I don't think I've met anyone who gets confused between b and d. (No offense, I'm just intrigued)