Sometimes, my wife enjoys giving me oral sex and sometimes NOT but it’s maddeningly unpredictable. I know she enjoys me giving her oral, but when she does me and I try to prolong it, for like 15 minutes or more, she puts an end to it and rolls off of me, and says, “Just put it in. I want it now.” I prefer oral sex, and I would like to eliminate regular intercourse and just have oral. How can I persuade her to have more ORAL SEX, and less regular sex?