My aplogies if I came across as disapproving, graham.
I had a friend who had a 'close' relationship with her dog- the dog was happy to apply it's tongue to certain parts of her body, to give pleasure. The dog didn't seem to mind, nor was it harmed physically.
I don't have a problem with that. Well I wouldn't want to do it or watch, but then I wouldn't do half the things people on here do- good luck to them.
I wouldn't want to even think about half this stuff, but so what?
As far as technicalities go, a dog will happily lick anything that smells good to it. Anything else- I repeat, get a blow up dog.
Tojo