You may also try a cock ring. You can get a pack of six different sizes on amazon. They help keep the blood in the organ. I'm also going to try one at the base and one just behind the head. I've found that head stimulation during sex determines hardness and duration. My theory is when I was young, cowgirl worked great as the head pushed hard on the uterus, but as I've aged and the erection is softer, it gets far less stimulation against the uterus. I'm hoping that keeping the blood in the head will make it pokey again. Just a thought.