Started by OCR member TeknoBunny, this oddity came to pass as a way for him to give soup (another OCR member) a hug and for TB and soup to retain their pantlessness, while avoiding any... other contacts. The best way to do this? Being backwards of course. And so, another OCR quirk came to pass.

In the end (no pun), it caught on and has become a staple among regulars.

-- The Coop, with corrections by endblink and arashi no tora