By Douglas Whitbread Donald Trump Jr has been slammed on social media for making sick not getting ‘wood’ remarks about ageing Joe Biden. The eldest son of the disgraced ex-president came up with the comments after quotes from a new book alleged Biden, 81, often joked the key to his happy marriage was “good sex”. The soon-to-be-released tome, titled ‘American Woman: The Transformation of the Modern First Lady, from Hillary Clinton to Jill Biden’, by Katie Rogers, is set to reveal intimate details about the lives of several presidential spouses throughout the years. And the eye-catching quip, re…