To last longer you need to have your partner bring you close to orgasm and then stop for a minute and begin again. If you do this often, then you will learn how to make yourself last longer. I usually ask people to hold off on intercourse and do it manually. Then after 2-3 weeks start with intercourse again. Most women really regard the penis as unsanitary.
Men shy away from oral sex for the same reason.
They might think that that part of the body is not clean. Having good experiences with oral sex is key. A lot of women do it mechanically. If you are not getting anything out of it, sooner or later you will find a reason not to do it anymore. To keep it going, you have to enjoy it and see that your partner is enjoying it.