To last longer in bed, you need to exercise some muscles in your body. Here are some muscles you should know and exercise you should practice.
1) pubococcygeus muscle (PC muscle) - this muscles is located between the scrotum and the anus. Imaging yourself urinating and try to stop yourself. The muscle gets hard if you do this technique. Hold the muscle and relax it after some time. Do this repeatedly to strengthen the muscle.
2) Yoga: this is also good, it helps open the limbs, joints and muscles which help provide relaxation and reduce stress.
3) exercise your back muscles: you need strong back muscles to last long in bed, engage in exercises like plank that strengthen not just the back muscles but the abdominal muscles too. Take time to strengthen these muscles so you can enjoy more time in bed.