Bind off purlwise question

I am making a sundress for my granddaughter, and am at the armhole edging which goes:

Work 4 rows moss stitch. Cast/bind off purlwise while working p1, then (p2tog, p1) to end.

Does this mean I purl one, then purl 2 together, pass the purled stitch over the purled 2 together stitches, purl 2, pass, etc.

I am at a standstill with my project until one of you out there can help me!

If you were working a regular bind off, you’d p2, pass one over, p1, pass one over, p1, pass one over . . . .

For this, p1, p2tog, pass one over. P1, pass stitch over, p2tog, pass stitch over, p1, pass stitch over, p2tog, pass stitch over. . . . .

Ingrid to the rescue once again ! Thanks.