In undergrad, I developed a love of the liminal space as a sexual arena. The "liminal space" being a transitional location, something of a grey area. For most of my last years and my brief stint in grad school (and really still today) the most enticing liminal space, for me, has been nature. Gardens, barns, forests, you name it—nature is sexy and literature proves it. Tess of the d'Urbervilles, Jane Eyre, and Lady Chatterley's Lover all include characters that let their guards down in the leafy greens. (For the record, it's not just sexually charged acts that occur in nature; sexual descriptors and adjectives are also very common when encountering or describing nature.)
Now, I'm a big fan of Downton Abbey, like many Anglophiles, and this season has me interested in liminal spaces yet again! Not just the great outdoors—although there was some groping on a bench and touching in a pig pen very recently—but also the kitchen!
I'd love, love, love to re-watch all the seasons and note the liminal spaces that show up, and how the differences or similarities in such spaces also include class. I think there is a brilliant article somewhere in there.