What can i do to improve in bed and last longer without having to ejaculate fast , and to maintain harder and better erections naturally ?

Multiple methods.: Simple methods for overcoming premature ejaculation is to use regular or desensitizing condoms. More natural methods are behavioral, such as the "stop and squeeze" method where sex is stopped and pressure is placed behind the tip of the penis, delaying ejaculation. Naturals ways to improve erections are to avoid alcohol, tobacco, and increase exercise.

Increase stimulation: to achieve and maintain your erection. You don't have to stop and "sqeeze," you can simply just slow down (or stop a few seconds). Think 1-10. 8, 9, 10 is when you're going to ejaculate, so slow down when you get to 8; allow yourself to lose up to 30% of your erection, then begin again. Do that 2-3 times before you allow climax. Best to practice alone the first few times!