You learned real fast as a dancer how much was the right amount to put on your shoes, because if you didn't put enough on, you were probably going to slip due to the low friction between your shoe and the stage.
Les danseurs apprennent très vite la quantité à mettre sur leurs chaussures, car si on n'en met pas assez, on a des chances de glisser, à cause de la faible friction entre la chaussure et la scène.