The dreaded bullion! Many folks are convinced that these are just not something they can stitch. Nonsense...but there is an easy road and a hard road.
But, when working with larger threads...like perle...it is hard to find a straw or milliner needle that has a large enough eye for the perle...without the needle shaft being so big that it doesn't leave huge holes in the fabric.
That's when you take the hard road...and deal with what you have.
Still, bullions can be done...without a lot of headaches. So, since this is not a perfect world where I live...and I have to use the best tool I can find..the hard road it is! An embroidery or chenille needle with the smallest eye I can get the thread through is usually my choice. I squeeze the thread at the tip to get it into the smallest needle I can...and the needle eye is long and slender...and the width of the eye is close to the same width as the shaft...but not quite the same.So, here is how I manage.
Needle up at the top of the bullion (or at least where you "want" the top to be)...and then, needle down at the bottom coming back up at the top again...without leaving the fabric.
Now, I grab these loops in my left hand...between my thumb and index finger. Grab the needle tip and pull the thread through...without letting go of the loops (you'll thank me for that later). Pull the thread until it starts to tighten under your fingers...(I had to put the needle down to get this photo).
The loops will be sitting above the fabric...and I like to put my needle under the line of loops and continue to pull my thread tightening them closer and closer to themselves. My needle is handy to use as a "nudge" to keep them tidy and in order. (If you forget to "pinch" the loops in your fingers first...this group of "loops" will just look like a tangle mess..but just keep pulling the tail thread...and use your needle to create that "nudge" from under the loops...soon, they will start to fall back in line and tighten up to something that resembles a line of loops once more.)
Repeat to stitch as many as you need. Remember that the direction and length of the bullion is set by the first steps...needle up at top...needle down at bottom, and back up at top without exiting the fabric. If you load more bullions than will neatly fit into this space...the bullion will curve. If you put too many in the space...it will have the center core thread showing out the bottom. For this flower, I stacked the bullions one next to the other...and started the next one at the half way point of the one on top. The first bullion is stitched at the end of the vine/stem...then the left side ones are done...then the right side ones.