I’m using US terms.
what you can do with it:
Clusters are the same as working 3 (or more) stitches together, so it’s basically a decrease. You can make these in almost any stitch because the premise is the same — we’ll be leaving off the finishing loop of three stitches until the end of the cluster and close them together at the end.
how to do it:
My examples are using double crochet. Chain the appropriate amount for what you want to do (I did multiples of 3+4). In the 5th chain from the hook, work a dc stitch, but don’t work the last loop. Work 2 more unfinished dcs in the next 2 sts, so that you have a total of 4 loops on your hook:
If you’re not wanting to use this as a decrease stitch, make sure to chain the appropriate number of stitches between clusters. Since I’m doing my clusters right next to each other, I needed to chain 2 in between my cluster stitches.