Strange mating ritual - laying eggs in tandem!

Yesterday I was fortunate to watch what seemed to me to be a very strange example of insect mating behaviour. On sunny days I keep an eye out for dragonflies at the pond and yesterday noticed a small red coloured one buzzing around and resting on the lily leaves. When I came back with the camera I saw that there were now two of them flying joined tail to head - they were flying in tandem. I was mystified. They couldn't be mating because the business end of the dull coloured one at the back was too far from whatever the red one at the front had in the way of wedding tackle. That was strange enough, but then something even stranger began. The red one, whom I took to be the male, seemed to be thrashing the water with the brown one. The two together were using a whipping action to bring the tail of the brown one down to the water for a fraction of a second - again and again, moving round the margins of the pond. I had seen dragonfly egg laying before and this was clearly what these two were up to, but why on earth were they doing it together? The male could not have been passing sperm so why was he there?

I got on the internet and looked it up. Whoever named the species must have been having a bad day for names:  this small red damselfly turned out to be exactly that - a Small Red Damselfly. Interestingly they are rare so this was quite significant. I also found a name for the behaviour "Oviposition in Tandem" but no explanation. The only  bit of evidence I could find was an extract from an experiment which seemed to show that the female gains nothing from having a male gripping her head with his tail. It must therefore benefit the male - presumably it is to prevent other males getting to her before she lays his eggs.

The next time I stood by the pond with the camera ready one male looked as if he was standing guard. He was perched at the edge of a lily leaf scanning the air above and around the pond with his enormous eyes, twitching his head from side to side. As soon as anything moved in his territory he was off chasing it. If it turned out not to be a female small red etc. he would return to his look-out post. If he caught a female the two would fly around the pond in tandem. I couldn't tell whether this behaviour always leads to egg laying, but it seems a reasonable assumption that the grip of the male would trigger egg laying behaviour.

I would be interested to know if anyone else has come across this - or seen on of these handsome little beasts.