As a rule she wouldn't discuss any detail but a while back her sister had a medical issue and among other things found sex painful. She was saying how she felt sorry for her deprived husband.
My Mrs asked her if she had thought of giving him oral, but she said she would be keen on that at all.(she's a bit reserved and prudish)
The discussion itself indicated to SIL that my wife gives blow jobs and I was surprised she was prepared to suggest it to her. SIL probably now understands why I'm such a happy soul.
In case any of you comedians out there suggest my wife volunteers to keep him happy, forget it.