During the Tsukihi Phoenix Arc of Nisemonogatari Yozuru Kagenui is seen not touching the ground. When she first meets Araragi and asks him directions to the cram school, she's standing on benches, and when she goes to leave, she jumps from bench to bench.
When she and Yotsugi Ononoki go to attack Tsukihi at the Araragi's house she is at first standing on the fence. When Tsukihi is seemingly killed by Ononoki she jumps on top of Araragi, pinning him to the ground, but she still stays off of it herself. When she and Ononoki go to leave, she is standing on Ononoki's finger as Ononoki walks away.
But when Araragi and Shinobu fight the two of them in the cram school she is walking on the ground. I am wondering if there is a pattern or condition to when she walks on the ground and when she doesn't?