A Back-Door Bob is one who prefers to utilize the anal passage over any other orifice. The term is not gender specific.
Tony - 'He proper loves loves putting things up his arse, man'
Terry - 'Aye, he's a proper Back-Door Bob like'
Back bobs a really bad photo on instagram with a bad captain that a 12 year old girl would usually post
Wow the dolphin was tight
That was a back bobs