if some one ask s you a quesrion you dont like to answer it.If you dont like to embarse him or her by answering it is not of your own business.What can be the other answer? .
Say "I don't want to discuss it" or "I don't feel comfortable talking about that" if you want to be polite. If you don't want them to ask you things in future, I suggest that you say something like "I think it's inappropriate to ask these types of questions".
If you don't want to answer a question, get advice from the politicians, they do it all the time !
If I am asked and I don't want to answer the question
I answer by asking another question. This is my way of avoiding answering the question and at the same time avoid embarrassing moments. This has worked for me all the time. It has been done to me too and
I know when to back off and drop the question.
I would say, "I am not comfortable talking about it"