So, I do not know what my problem is. I thought I figured it out and solved it, but after last night clearly I didn't. When I'm with a girl, I become erect very easily, and usually stay erect for awhile. However, once the girl takes out my penis I don't stay erect long at all (maybe a minute tops) and I do not ejaculate. A lot of times my penis goes soft and then a couple minutes later it will become hard again, then the girl starts playing with my penis and then it will go soft again. Last night the girl said, "I don't get it, you keep getting hard when I'm not touching you, but then when I touch you, you get soft." It is really frustrating when this happens. I am 20 years old and in good health, so I feel like this should not be happening to me.

Is there anything I can do to fix this problem (without the use of drugs)? The only thing I can think of is to stop masturbating.