Heel knitting question

When knitting socks, and making the heel flap, it says S1 K1 and I want to know if the S1 should be a purlwise slip, or a knitwise slip and yarn front or back. I I always slip purlwise and move the yarn forward to do it, but I wonder every time I do it. Thanks and stay well, S

I had this same question recently and I was slipping the stitch knitwise but I was told that it’s really supposed to be purlwise. When I tried it this way it worked out better. I don’t think it makes a huge difference either way but I think it’s supposed to be purlwise…Oh yeah, keep yarn in back b/c you’re going to knit the next stitch…

Good luck!