Professionals know that henna must stay on the skin for 6 - 8 hours to get a great stain. Usually, henna wants to flake off once it's dry. There are some regions where the weather is so perfect that, given enough sugar in the paste, the henna can still like concrete... But in the crazy weather of Canada, that's a rarity!
3M paper medical tape to the rescue!
Paper medical tape allows for much more freedom of movement without the constant worry. It makes paste removal a breeze - no need to scrape off with messy oil & henna bits everywhere.
The most important reason why I prefer medical tape over lemon-sugar: it doesn't attract BUGS!