If you want to add a trim (as opposed to piping), when and how would you do that? Thanks.
You attach it in the same way as piping,
I purchased a day's viewing of the piped cushion videos yesterday and today have a lovely cushion. I am now confident to make more. As you say in your tip the videos are extremely well worthwhile and great value for money! Your written tutorial is clear and extremely high quality, but nothing replaces a good demonstration. Your commentary and hints are very helpful and the close-up shots are superb. Thank you so much from a grateful sewer. PS I haven't tacked for a long time but followed your advice to do this on the zip, and got superior results.