I was woken up this morning at around midnight by something disturbing, yet hilarious. One of our Calico cats, Cassie, was sucking on my ears. First my right and then my left a short while later. Apparently she was trying to nurse! I thought she'd put two and two together (figuratively speaking...nobody's ever proven cats can do math) and realize that since nothing was coming out that it was pointless). If I hadn't been so sleepy, I would've laughed myself limp.
A lady at work told me some cats will do this as a type of soothing activity. Glad I could be of service, Cassie!