BERLIN (Reuters) - Hundreds of fans of German club Borussia Dortmund waved huge inflatable penises at local rivals Schalke 04 on Saturday above an abusive message for their hosts. The pink blow-ups and a huge banner in Dortmund's yellow and black suggesting Schalke fans should procreate with themselves added a splash of colour to the dour 0-0 draw between the two Bundesliga sides. Schalke's stadium in the Ruhr Valley city of Gelsenkirchen will host four group matches and a quarter-final at the World Cup in Germany in June and July.