It's not really a pickup line so much as a fait accompli.
CONTEXT: The morning after I met Louis (which is an excellent story for another time), he and I were rolling around in bed after he woke me up my fingering my pussy until I came. His hand is in my hair, I am kissing the inside of his thigh, then I lick the underside of his cock from the base to the tip. I am looking him straight in the eyes as I take almost the entirety of him into my mouth.
THE LINE: “You're such a seductress.”
DID IT WORK: I can't think of a rubric where it didn't. I swallowed his orgasm, he rolled me over and sucked my clit and fucked me.
We have repeated this experiment in many different iterations since.
I'm pretty sure that means it worked.
NB: My friend Siobhán is quick to point out that the oral sex that you are receiving at that moment is the greatest oral sex in the world by virtue of the fact that it is happening NOW. I like to think there's more to it than that.