Looks like either a PH meter or one of the sensors that people who are blind use to keep from overfilling a glass. Beeps or vibrates when it touches the water or whatever.
Or it could be something even more sinister, like a beverage negative reinforcement facilitator. Every time the liquid touches your lips you get an electric shock. After a few weeks of Pavlovian conditioning your lips should tingle at the mere thought of a gin and tonic...
"The pigeons in BF Skinner's laboratory were political prisoners!"