This can also help you in boosting your sexual stamina. This is the best and easiest way to strengthen your pelvic muscles. The stronger your pelvic muscles are, the more are chances of increases sexual stamina. This also ensures that you have a stronger erection.Trying body-weight squats can help in strengthening pelvic muscles. If you want to further increase your stamina, you can also try full squats or one-leg squats.