One of the reasons I chose an Adjustoform Supafit De Luxe model when I bought my dressmaker’s dummy was that it had a chalk dust dispenser for marking hem lengths. Four months after purchase, I’ve finally used the chalk dispenser.
As you can see, trial and error was involved. My first attempt made quite a mess. Turns out, the dispenser positioning is adjustable and it needs to be really near your fabric:
One small step for man, one giant leap for sewing kind.