The phrase derives from track-and-field events in which athletes are required to place a foot on a starting line and wait for the signal to go. Race officials used to shout “Toe the line!” where now they shout “On your marks!”
Since entering the language, the idiom has developed to mean do what is expected or act according to someone else’s rules or expectations.
@NormanDunbar
Except if you're a German native speaker, Dore would be pronounced Dor-eh (see Porsche), I'm sure there are other variations in other languages. It's not winnable.
@econads@dalehandyman True! I worked in München for a while at BMW Bank. My German speaking is, sadly, abysmal. Everyone spoke better English than I did and insisted on speaking it to me. Most polite.