These things have happened in the past:
-girl taps me beneath my knee once.
-girl holds foot against me on the part of my leg that is under the knee and above the foot. I don't know what that part is called. I always freeze up, not wanting too inadvertently reject her or do anything uncouth in a university setting.
-one time a girl was sitting on a spinny sort of chair, and span so that her feet briefly hit mine.
-a few times a girl sitting next to me had needed to leave the room. Getting up from the chair involves bruising my legs for a split second.
-I was at this networking thing watching a debate, and a girl stretches her legs so her toes are under my chair. I'm sitting with my legs in front, do there's no touching, but it's still a bit weird.
Sometimes this sort of thing is accompanied by a smiley, friendly demeanour. Not always. It usually makes me feel self-conscious.
I think I know what this all means, but I want internet advice before I reach any conclusions. If all this is some sort of covert courtship signal, what should I do the next time this happens?