This style of pocket opening does not fall under Tereson’s patent. It’s probably the most popular alternative to pocket openings.
When you cut out your microfleece, you’ll cut it out on the fold as instructed, but you’re going to cut off the top, the line for the slit style pocket opening is a good guide.
Next, cut out a strip of microfleece (I’m using suedecloth in these photos) about 2.5" high and the same width (cut on fold) as the diaper body as shown:
I like to lay the waterproof layer down so I can line up the two pieces of microfleece accurately:
Laying your microfleece layers right side up, lay the strip right side up on top of it. It will overlap:
Pin carefully in place (don’t pin to the waterproof layer!) Using the elastic placement dots on the pattern, pin the envelope opening shut aligned with where the elastic will be sewn into the seam allowance above.
Stitch through the microfleece layers only from the wing edge into where you marked with the pin. This will keep the pocket opening from being too wide and flapping crazily:
When that’s done, pin the opening shut and layer your microfleece and waterproof layers right side together and complete the rest of the instructions in your pattern, omitting the slitting of the pocket opening.
**You can finish the edges of the envelope opening before stitching it together but neither microfleece or suedecloth will fray, so it’s up to you.
I didn’t have time to finish the diaper for you, but here is the right side of the microfleece layer, the opening is easy to access and lays neat when the whole thing is sewn together: