Without knowing the entire exchange, I can only guess. There's an American English expression that if someone is telling you something to impress you, or get your attention, (and it isn't necessarily true) he/she might "hand" or "feed" you a "line." For example, it could be about how beautiful/handsome you are, or how much smarter redheads are (and you're a redhead), or how important his/her job is. The whole idea is that what is said isn't true but is only said to impress the other person. Take a look at this link.

Hope this helps.

This is the context: <a href="https://genius.com/Friends-tv-the-pilot-annotated" rel="noopener noreferrer" target="_blank">https://genius.com/Friends-tv-the-pilot-annotated</a>;

In short, Monica dates Paul, the wine guy. At the date the following scene takes place:

<em style="color: rgb(34, 34, 34);">PAUL: </em><em>Well, ever-ev-... ever since she left me, um, I haven't been able to, uh, perform... (MONICA TAKES A SIP OF HER DRINK) Sexually.</em>

<em style="color: rgb(34, 34, 34);">MONICA: (SPITS OUT HER DRINK IN SHOCK) Oh God, oh God, I am sorry... I am so sorry...</em>

<em style="color: rgb(34, 34, 34);">PAUL: It's okay...</em>

<em style="color: rgb(34, 34, 34);">MONICA: Being spit on is probably not what you need right now. Um... how long?</em>

<em style="color: rgb(34, 34, 34);">PAUL: </em><em>Two years.</em>

That means: He tells her that he didn't have sex since his last girlfriend left him. For two years. Next morning we find out that Paul spend the night at Monica's place and her friends witness him leaving:

<em style="color: rgb(34, 34, 34);">MONICA: I had a really great time last night.</em>

<em style="color: rgb(34, 34, 34);">PAUL: Thank you. Thank you so much.</em>

<em style="color: rgb(34, 34, 34);">MONICA: Stop.</em>

<em style="color: rgb(34, 34, 34);">PAUL: No, I'm telling you. Last night was like, it was like all of my birthdays, both graduations, plus the barn raising scene at Witness.</em>

<em style="color: rgb(34, 34, 34);">SCENE 6: IRIDIUM (JUST MONICA, WORKING)</em>

<em style="color: rgb(34, 34, 34);">(ENTER FRANNIE)</em>

<em style="color: rgb(34, 34, 34);">FRANNIE: Hey, Monica!</em>

<em style="color: rgb(34, 34, 34);">MONICA: Hey, Frannie. Welcome back! How was Florida?</em>

<em style="color: rgb(34, 34, 34);">FRANNIE: You had sex, didn't you?</em>

<em style="color: rgb(34, 34, 34);">MONICA: How do you do that?</em>

<em style="color: rgb(34, 34, 34);">FRANNIE: Oh, I hate you. I'm pushing my Aunt Roz through Parrot Jungle and you're having sex. So... Who?</em>

<em style="color: rgb(34, 34, 34);">MONICA: You know Paul?</em>

<em style="color: rgb(34, 34, 34);">FRANNIE: Paul the wine guy? Oh yeah, I know Paul.</em>

<em style="color: rgb(34, 34, 34);">MONICA: You mean you know Paul like I know Paul?</em>

<em style="color: rgb(34, 34, 34);">FRANNIE: Are you kidding? I take credit for Paul. </em><em>You know before me, there was no snap in his turtle for two years.</em>

<em style="color: rgb(34, 34, 34);">(CUT TO THE GANG MINUS RACHEL AT CENTRAL PERK)</em>

<em style="color: rgb(34, 34, 34);">JOEY: (PERCHED ON THE SIDE OF THE SOFA) </em><em>Of course it was a line!</em>

<em style="color: rgb(34, 34, 34);">MONICA: </em><em>Why?! Why? Why, why would anybody do something like that?</em>

<em style="color: rgb(34, 34, 34);">ROSS: </em><em style="color: rgb(34, 34, 34); background-color: rgb(255, 255, 0);">I assume we're looking for an answer more sophisticated than, "To get you into bed.</em><em style="color: rgb(34, 34, 34);">"</em>

@Max

The line Frannie said about the snap in the turtle isn’t a common idiom but most likely made up for the show: <a href="https://youtu.be/n0bCAYlLlWE" rel="noopener noreferrer" target="_blank">https://youtu.be/n0bCAYlLlWE</a>;. I think it means that Paul was impotent (not able to perform) and thanks to Frannie he gained confidence and now is a great lover. She mentions that she „takes credit“ for him, so she sees his performance as her achievement.

@Miriam

Thanks for the explanation, I thought it was some kind of slang. But it turns out this phrase was invented by the creators of the series.:)

I understood that the word 'line' here means 'just words'. It was much more difficult for me to understand the idiom that Monica had uttered before - 'Before me, there was no snap in his turtle for two years'. I'm still guessing what exactly that means.:)