For a fig stem, you would probably want to draw 2 curves and use sweep. Here's a quick overview - I drew one curve and one circle like this.
After you have drawn those 2 curves, select the circle, then click Construct / Sweep, then select the path curve and push Done, and Done once again after you see the Sweep options. That will create this sweep:
You can adjust the rail curve, or put in additional sweep profiles to customize it some more. If you place the sweep profiles off to the side away from the rail curve, then MoI will automatically move them into position perpendicular to the rail.
Hope this helps!
If you have any ideas on how stem creation could be made more intuitive than this, please let me know!
