The Elusive Fifth Dose

Have read posts on here of people managing to get a fifth dose from the UK KwikPen. I tried to do it this morning by just twisting the twisty bit really hard.

It worked on the way out (beforehand), but not on the way back in (during the injection). Everything got stuck part way through, and nothing I did would move it. I think I’ve got about 4.2 doses out, so still about 80% of a fifth dose remaining which I’d like to avoid wasting.

Am I doing something wrong? Is there another way? I’ve read of people sucking the excess out with insulin needles, but I’m not sure what these look like and how to use them. And a bit scared 😱 too.

Confused.

Thank you!