A Dany for a lustful line where we may not learn about my lineage for a while. And by the time we do, it no longer matters because we truly love one another.
An Arya or Sansa to learn that they are no longer related to Jon by blood, and can finally act on that deep-seeded crush that they had for him. Finally able to give him a night that neither of them will ever forget.
An AU-verse Caitlin, after finding out the truth about Jon, feels horrible about how she treated him and willingly gives herself to him to use however he sees fit. He truly is surprised by just how willing she truly is.
A Cersei to try and seduce him in to becoming her King over Dany, with no shame about using her body or anything else Jon could hope to have.
Up for other lines too, just ask. But clearly, smut is the biggest draw.