My sewing machine has an auto-thread cutter which pulls my thread ends to the back of the quilt and trims them to 3/4 inch long. I developed the following method to bury the thread ends inside the layers of the quilt.
I used a super long needle threader which is not necessary, it’s just what I had. An ordinary needle threader would work the same way. The key to these steps is inserting your needle before trying to thread it.