Best friend becomes boyfriend but he's horrible at sex

My best friend and I are now in a relationship, we have sex and he's a decent size , I would think the size he is he would make me feel good but it doesn't and he cums so fast. Now he is a veteran so he said he would talk to the VA about medication but it's how he's not moving his hips he pushes than stops or if I'm like oh baby push harder he doesn't go in and out harder he just stays in and keeps pushing which he's already in me so it's not doing any thing. How can i teach him how to fuck me good? 🤦🏻‍♀️ He knows and totally understands and is up for learning. Ladies please help me 😭