Ernie grinned at the psychic remark. "I wish. I think I just spent a little more time with those Durmstrang blokes than you did in Fourth Year," he explained with a wink.
He nodded. "I can see that, having a cauldron just for that. But then we can also transfigure just about anything into a huge cauldron, or at least something that looks like one. Actual cauldrons need to meet certain specifications to be able to handle potionmaking, but for a hot tub, just the look will do, I suppose."
Ernie followed Harry's pointing and his eyes landed on the figures in the cauldron. One of the witches giggle and gave him and Harry a suggestive wave. "Sorry, lass," he said, shaking his head. "I don't think I swing your way. Though maybe my friend here might like to watch a bit," he teased with a pointed look at Harry.