You must buy yourself one. I bought one from Amazon months ago, they're wonderful. I've only used it once, a couple of weeks back, on a slow puncture I was topping up weekly for months. I did have it repaired in Keit Duffy's place in Swords previously when I had to buy a tyre for another wheel of a Sunday but it didn't last.
Finding the hole was the hardest part as it was a very slight leak from the previous plug. Having never done one before I had three attempts. I pushed the first strip in too far and lost it inside the tyre, the second seemed to work but, after a cup of coffee, I decided I wasn't happy that I'd pushed the strip in far enough - it does retract a little as you pull your little tool out. The third was just right and hasn't lost any air since. I think the trick (if there is a trick) with them is to let as little air as possible out before inserting the strip i.e. leave the reaming tool in the hole till you have the strip ready and, after inserting the strip, withdraw your little tool with a swift deliberate jerk. I think the air pressure from within is key to achieving the necessary seal. I left my little electric inflator attached throughout the process for good measure.
