I tried the swap three times. Once, I missed the timing, and the printer ran out and just kept printing air. Once, it seemed like it was going to print seamlessly, but the print mysteriously failed later. And once, I tried to switch from dark chocolate to white chocolate, but the chocolate seized inside the nozzle and refused to come out.
In practice, I found it far easier to simply print objects that would use up most of a stick in one go, then use the remainder to print a second partial object and just pop that directly into my mouth.