There are a number of my clients who are very sensitive and can orgasm quickly.
On their first visit it helps if they make me aware of their sensitivities and we take things very slowly. Lots of teasing, gentle touch, blowing, licking light scratching on all other parts of the body besides the groin. Be moving their awareness away from the groin it reduces their anxiety of arriving early. They will also communicate when things become to intense and I will reduce the stimulation.
Creating a sense of ease for the client will aid in extending their pleasure time. A gentlemen who visits me once a week has now become so comfortable with me, he can enjoy penetration for almost 5 minutes. Compared to his first visit where he came before intercourse.