Just a sexual topic that allows you to implant some pretty sexual thoughts during a conversation. Play with it however you like this is just an example of the topic, you can mix around the facts and descrptions where ever you like:
"Do you close your eyes when you kiss someone?"
"Why? does it change how it feels?"
"Ill let you in on a secret, i sometimes peek!
""Well do you close your eyes during sex?"
"We close our eyes because when you shut your eyes, your brain shifts to your other senses - the sense of touch (and feel) for sure, plus scent" - Get descriptive here "Intense" etc
You can go physical here and do a little test, touch her arm with her eyes open, then closed for her to compare, or something more sexual depending on what she will allow you, kiss on neck etc
"Its interesting, 95% of people close their eyes when they kiss, but only 60% say they do during sex...and it was mainly women"
"Imagine we are having sex, you are focused on the emotions during sex, where as men are more visual which can help explain the figures"
I could keep going but it's a swift way to quickly escalate from a light hearted question about kissing to some strong stuff. Would like to see your contributions about what you could ask or say during a conversation like this.