I’m 58 and have difficulty ejaculating. Sometimes it happens with oral or with intercourse, just not very often. My companion really wants me to come inside her, and so do I, but too often, I lose my erection before the big moment. It feels like there’s a lack of stimulation when I’m inside her. I don’t “feel” anything. Lubrication isn’t an issue, she has plenty and we aren’t bashful about using synthetic lube. For reasons of knee pain and the fact that we’re overweight, the only intercourse position that works is her lying on her back and me on my right side with my torso at a right angle to hers. Missionary hurts my knees and I’m too tall, compared to her, for doggie to work comfortably. Do you have any suggestions to continue the stimulation on the head of my penis to build up an ejaculation after penetration?