i'm going to share how i bury thread tails. this technique will work for burying threads in a LA frame or freemotion with a DSM. (this technique should not be used if your thread color is contrasting to the fabric color and will shadow through the quilt top fabric. rememeber the varicose thread post?)
the tools i use is a 9inch doll needle and that threader thing. i use the doll needle because it's long and is easier to manipulate through the quilt sandwich while it's still in the frame. it also has a large eye which makes getting the thread tails threaded easier (read: it is eye strain friendly). i bought the threader (all metal) at my local hancock's (in the embrodiery aisle). i had a plastic one before that really didn't work as well. make sure the one you buy will fit in the eye of your doll needle's eye.
this technique will work with long or short thread tails...take the two thread tails and tie a knot in them (i use a simple square knot, going thru the loop twice in the second knot) insert the needle in the same hole the last stitch is in. slide the needle in the batting so that the buried threads will be in the batting. slide the needle down until the eye is even your knot.
wha-la...buried tails...i would do the same with the thread tails from beginning a line of stitches, burying all four tails at the same time.
i bury tails where if i did the little backstich knot it would be too noticable. (ie: high contrast between the fabric color and thread color)
i used the self-threading needles and found that the eye pinched the thread and tended to break it to the point of being too short to bury anymore.