It wasn't legalised between men & women until the Criminal Justice and Public Order Act 1994, the one that had the 'repetitive beats' definition of music, limited the right to silence, included simulated images in the definition of child porn, stopped councils having to provide sites for travellers and also reduced the age of consent for sex between men to 18.
When a pair of friends heard about the anal sex bit at a meeting, they went off home to have it...