RT (Right Twist)

[Lisa Perry]

I'm confused on my pattern instructions. It's called Cross-Stitch Squares by Joyce Englund from the book Quick Knitted Afghans page 138.

It wants me to do a right twist (RT) I've not done this before.
Right Twist (RT): K1 in front of 2nd st on LH needle, k1 in back of first st on LH needle, sl both sts off needle at once.

I've tried using another needle like a cable stitch but what does it mean by slipping both stitches off the needle at once? Am I confusing this with a cable stitch?

Thanks