Odd sights in Hay

There was nothing immediately unusual about the man going into the bookshop. He was wearing a rucksack, which is fairly normal round here - but there was a blue tube coming out of the rucksack, with a mouth piece round the front. It was probably for water, but it looked as if he was an alien who needed to breathe their own air occasionally in order to survive on Earth.

Then there was the group of girls walking down Backfold - one of them holding a giant, inflatable penis....
Where were they going? What was it for?