Why is it so hard for people to ask their partners about sex? If I want to try something new I talk to my wife about it.

It really is that simple. Sit her down and ask, "honey, what do you have against me performing oral sex on you?" I imagine the problem is she was raised in a family where sex was dirty, and you just didn't touch the naughty bits. She has this so ingrained in her that she is uncomfortable with you getting up close and personal with her vagina. She can't relax and she can't understand what you can possibly get out of wanting to lick on something she has spent her whole life convinced is dirty and nasty.

Hell my wife love love loves for me to go down on her but only AFTER she's bathed. If she doesn't feel she's clean down there she has a hard time relaxing enough to get any pleasure from it.