Robb was telling me about an experience he had this week at the pool. He got into the water, and was struck with the feeling that something was different. While the sensation was notable, he couldn't identify what the difference was. (He did actually check to see if somehow he had forgotten to wear his swim trunks.)
What seems to have happened is that Robb has crossed a tiny invisible barrier in terms of neural regeneration, and now has slightly more sensation in his legs. He's aware, for the first time since his accident, of the movement of his leg-hairs in the water.
Of course, any time sensation starts to return, it fails to do so in an orderly fashion. Right now, Robb is going through another period of increased muscular spasticity.
His butt, in particular, is not happy.