‘Tits. Out. For the boys. Tits out for the boys. Tits. Out. For the boys. Tits out for the boys.’

I started out softly but by the end I am screaming at the top of my lungs because I am 19 and everyone around me is doing the same and crowd enthusiasm is contagious. We’re standing on the bank of a river and it’s a sunny day. There are hundreds of us, clustered in and around a marquee. At the centre are two long, rectangular tables, a line of women at each.