Reddit mentions of Understanding Human Sexuality

For starters, and I hope this doesn't come off weird, masturbate. One of the best ways to be better with a partner is to know your own body and to learn what you like and how you like it. Second, communicate with your partner about what you want and need before, during, and after sex, and ask her what she needs from you, as well.

I would also suggest checking out this book - Understanding Human Sexuality (https://www.amazon.com/dp/0073382620/ref=cm_sw_r_awd_W7XSub0BNY67H). I studied it for Psychology of Human Sexuality, and it provides excellent and subjective info on everything from the biological mechanics of sex and reprpduction to STDs to relationships and dating. There is some info in there about counseling and therapy, as it is a psychology textbook, but you may even find value in that.

And remember, not every time you have intercourse will be amazing. Sometimes there's simply no spark, and sometimes it's over too quickly. It happens to everyone, and this is another area where communication is key.

Best of luck!