I think it's all mental. My GF used to be the same way, could never get off during sex. But she was always worried about how I thought she looked, etc.... Now that we've been together for years and years, she's able to relax and really get into it and she'll go 4-5 times in a night. For a woman I think their mind has to be into it just as much if not more than anything else. For a man it's like "Hey this feels good" *squirt*