How to decrease this Fisherman's Rib stitch

I’m using a Dutch version of the Fisherman’s Rib stitch which I love for scarves and blankets as it is really warm, the end result is thick and heavy, looks the same on both sides and is forgiving with mistakes.
Now I want to make a hat, which requires decreases, and I don’t know how to do it! The pattern is like this:
Cast on even number of stitches
Row 1: k1, k1, yfwd, sl1p, k1
(You now have alternating “normal” stitches and “double” stitches on your needle, I call those dst)
Row 2: k1, kdst, yfwd, sl1p k1
Repeat row 2 until desired length.

Pictures (with explanation in dutch) can be found here:
www.breien.nl, on left-hand side click on “breien leren”, use scroll bar on the right to scroll all the way down where it says on the right-hand menu (in blue) “De patentsteek”, click on that.

So how to decrease without switching to stockinette stich?

Grateful for any advice!

Thanks,
Miriam.

The brioche stitch site has instructions for decreases and increases; Fisherman’s rib is another name for brioche stitch.