By that, do you mean
a Norwegian Blue?

A Norweign Blue and a moribund entertainment are referring to the activity but as seen from across the gender divide.
A norweign blue was a prank developed by the female students of Oslo University. During rag week they stood by traffic lights in the buff, when the front cars stoppped male drivers were then offered a bucket of cold water, a soapy sponge and 30 seconds to rub the student down.
What Raak refered to is the jealous wives in the passenger seat death like, arms folded and grim ashen faced not looking.

My brother who is more widely travelled is rumoured to have had a great time with a Swindon plank is this possible?

Only if one is into necrophilia.

Someone I met in a bar urged me to Repurpose my assets. I backed away slowly -- did I do the right thing?

I think it is highly likely that you did precisely the right thing. It's a a gay chatup line.

Years ago I was offered a Rum Baba. I had no idea how to conceal my awful ignorance.

A Rum Baba, at least if you come from Wales, New Zealand or Australia, is a strange (read very strange) sheep. Whilst we are on the subject of strange phrases, I was up the local shops the other day and one of the proprietors mentiond a Virtual Ending. Did I hear this correctly, or is there something that I am missing?