I think the OP on the Bumsnet thread is a fella on a wind-up.
"Why not do some research into anal sex. You might find you like it."
WTF?? WhatTheVery****ing****? This is mumsnet! Are you quite normal?
Are you going to suggest I get into a leather outfit and take a **** on a glass coffee table next, because I might "like it".
Dear Lord in heaven