Adding yarn colors for heel flap

After a long break from knitting (get all prepped and newphews break the needles i need and then we moved and guess which box got left behind grrr.) I’m ready to do socks in color with a slipped stitch heel pattern. I know how to add yarn but for the life me I can’t figure this out. When starting the heel flap i add the yarn, usually by tieing a slip knot (the way amy does in her duplicate stitch video). When it comes to picking up stitches its hard because of the knot and when i undo the knot to weave in, its a mess (the tails are on the front, if i twist the tail i get a uncomforatable bump etc) I have tried just knitting with the new color without tieing it but then i have a loose tail so when i pick up stitches if im not careful i can pull the yarn through. Maybe I’m just out of practice cause I can change colors for the toe with no problems…so far. but thought I’d ask…What’s your prefered way to change yarn colors for the heel flap of a sock that keeps the slip stich edge intact and any tips on how to weave that section in. Thanks! p.s i pick up through the back loop only if that makes a differnece

Try leaving a bit longer tail so it’s less likely to pull through and snug up the loose end just before you pick up sts. See if that helps.

Thanks so much. That basically fixed it and it was so easy. Guess I have to get back in the swing of things. Thanks again.