Hello thanks for asking from Healthcaremagic.com I can understand your concern. With advancing age sexual functions start decreasing progressively. You are getting good erection during oral intercourse but during intercourse both of you are not reaching climax. First cause of these symptoms is probably associated anxiety and psychological reasons. This should be dealt properly. Try to remain relaxed and avoid thinking that you will not reach orgasm. Spend more time in foreplay and this will make hard erection and you will see improvement. More and more foreplay will relax her vaginal muscles and will increase lubrication. This will aid in easy penetration and she will enjoy sex. If there is dryness in her vagina you can ask her to use KY jelly during sex. If problem persists then Sildenafil or Tadalafil can be used. These medicines will help in strong erection. Please take prescription of your doctor. Thanks. Take care