Rye Lee's right; people flirt for a whole variety of reasons... but that doesn't discount the fact that flirting sets up the base for escalation.
I'm all about ADVENTURE, so I encourage you to see where the night takes you, metaphorically (maybe literally) speaking.
You're doing a great job sexually framing stuff in class. Keep it up and see how far you can take it. Now what I would do is work on proximity. See how close you can stand next to her while talking to her without making her uncomfortable. In fact, go for the SEC in SECT (Gunwitch method).
www.gunwitch.com If she kinos you, reciprocate with the T part of SECT.
Thank to you, I'm actually starting to game one of my teachers just for the sake of taboo.

She's only a first year PhD student and I've already done dirty things with women a little older than her, so this is still in my comfort zone even if it's taboo.