How to decrease when crocheting the corner-to-corner stitch

Someone on the Creative Crochet Crew -- The Group Facebook group was getting in a muddle over where exactly to place the slip stitches for the decrease when making a corner-to-corner blanket. In order to try to help, I did some photos which I thought I'd also post here, so I have the tutorial handy in case anyone else has a problem.

1. Here is what the piece looks like as you finish the last of the increase rows. Until now, each row has been getting longer, but from now on, we're going to decrease to stop the piece growing and instead get it to narrow down to a point.

2. Turn the work and slip stitch into the trebles (US double crochet). I find that crocheting into just the two nearest the 3 chain loop works best.

3. Now slip stitch into the 3 chain loop which is on the same block.

4. Chain 3. You can see where the next block will fit. The decrease has started to make a straight edge and from now on, the project begins to decrease in width.

5. Here the decrease is complete and we're working the rest of the row.

At the end of this row, you can either carry on increasing, in which case you will end up with a long rectangular strip, for example for a scarf. Or, after you have reached the end of the row and made the turn, you can start to decrease at this side as well.