Slip stitch.... sewing seam?

Hi! I’m supposed to slip stitch a sweater sleeve up, and I don’t know what they mean by “slip stitch.” Is it the K1, S1, psso? How does that work for sewing seams? Or is this crochet?

At first I thought I was supposed to whip stitch, but I can’t use that because I need to keep the yarn attached to both my work and my ball of yarn while I do it. Anyone know how? Thanks!

Probably like crocheted slip stitch. If it’s a baby sweater sleeve (there’s one that calls for this type of seam) you can cut your yarn, leaving enough of a tail to seam it up, then do the next section with the yarn end, it doesn’t have to be attached to the sleeve seam.

But after I sew the seam, I keep knitting with that yarn into the main body of the sweater. Should I cut the yarn and then re-tie?

This is a baby sweater. If you want to know how the pattern puts it:

[I]Bind off /I[I] leaving last stitch on needle. With right sides together slip stitch sleeve closed being careful to close up all the holes at the underarm. Place last stitch on left hand needle. Knit 2 tog and knit across to next marker.[/I](That last part’s knitting into the body of the sweater.)

Still confused. Does this mean crochet?
Thanks so much for any help!

Yep, that’s the one I thought it was. You could do the slip st kind of like picking up sts and binding off all at once, or use a hook to do a crochet slip st. But it’s probably easier to just leave it, cut the yarn and sew up the seam. Then take the end of yarn and just start knitting on the back stitches. You don’t need to ‘tie’ the yarn anywhere, leave about 3-6" to weave in later and just knit the stitches. The end won’t come out.