Mr Bum

Whilst walking around one of those budget book shops at the weekend I spotted the following image.  I posted it up on Facebook with the comment "Finally, a gay Mr Man at last!".  It didn't get any response.  When we got back my neighbour said, "I saw your Facebook post and laughed a lot, I didn't dare comment though".

Am I becoming one of those old people that don't know where the boundaries are?  Is using 'Bum' as a verb relating to sex offensive now?  People in the generation above me still think it's OK to call Black people 'Darkies', I don't want to become one of them!  But then again I don't want to be a sterile w*nker that only laughs at jokes out of a Christmas cracker!