Best & Trusted method for adding yarn?

I am knitting a baby blanket with Knitpicks Mighty Stitch bulky. This yarn is machine washable and dryable so it’s perfect for a baby. The Yarn is a little slick and I am worried my normal method of adding the new yarn isn’t secure enough …I usually add the new yarn and knit with the old and new for a few stitches then drop the old and continue with the new. I did that when adding the first skein then knotted the tails as an after thought. The knot has already come untied just from me moving the completed part around while knitting.
I did attempt using a magic knot and I didn’t trust it, lol.
So what tried and true method do you recommend for adding a new ball of slick-ish yarn that will get beat up in the washer and dryer?

I’ve just knit a baby blanket in Mighty Stitch and I had problems joining new yarn because of the bulky weight. I ended up overlapping the yarns as you describe but only for one or two sts. Then I used a method Jan taught me to weave in the ends.
Split the yarn into plies (I think it’s 4 for this yarn) and weave the plies in in different directions. That worked very well to secure the yarn ends. If it hadn’t, I was going to try a stitch or two with sewing thread to tack in the ends.


Thank you! That yarn is soft but slick.

Yes, so be sure to weave in for a couple of inches back and forth.