Really handy! It's my thumb!
These leaves are satin stitch. The tendrils are B.E. Outline Stitch (floss held below the line of stitching when you are using Z-twist rayon threads for Brazilian dimensional embroidery) to give a smooth appearance to the vines.
Satin stitch, working with these twisted threads, always seems to look prettier when the twist is the same for each stitch. A "true" laying tool is ideal (I use my thumb and forefinger) and you can always improvise with whatever is at hand (pun intended).
Whenever I stitch, I use the stab method since I work on a hoop or frame, my left hand poking the needle into the fabric, and my dominant right hand pushing the needle up from below. Then I use my left hand to lift the floss once or twice, just before settling it into place.
Another way to accomplish the identical twist for each stitch is to twirl the needle to "unwind" the floss slightly.
To work a doodle cloth sample of the satin stitch, draw an oval shape and use Lola (because the twist is more pronounced). First, make all the stitches across the shape without letting go of the needle -- around and around and around -- you'll see the floss gets "stringy" after a few stitches.
Now make a second sample and twirl the needle to untwist the floss or lift the floss before settling the stitch into place. You'll see that this is much more beautiful and gives a real "satiny" appearance to your satin stitch.
Here's another little thing that most people probably already know about:
See that tiny backstitch in the middle of the leaf? I'll do that sometimes when I start a shape. Mostly, it hides the knot and you won't have a floss tail shadow. But it also helps to adjust the tension slightly on the first stitch so all stitches evenly match.