Honestly, I've said to every girl I've had sex with, but as a man of substantial girth, it always has some level of truth when I say it to the girl I'm with. That being said, there are certainly girls that it has been a lot more true about than others. It's just a kind of dirty-talking thing, like women commenting about how big a guy's cock is. I'm sure they really genuinely mean it with some guys, and with others they're just telling the guy what the guy wants to hear.
