Well, I'll try to summarize the story. It won't be as funny as it was on TV though. Here it goes: Jerry and Elaine were talking about their old relationship, and Elaine confessed that she "faked," surprising and irritating Jerry. Jerry begs her to give him a chance to prove his manhood (by doing you know what). Meanwhile George is seeing a new woman whom he wants to impress. Throughout the episode, mangoes are subtly presented as a way to make a man more potent (you know... down there). I'm so sorry that I couldn't do justice to this incredibly funny episode, but that's the gist of what I remember.
Chris