The act of sitting in ones room or bed completely instilled in darkness much before the time they plan on going to sleep. One who bat-caves often keeps them self occupied with a computer or videogame to play on. Music is not typically listened to by the bat caver and social conversation does not usually take place. It is described by common bat-cavers by relaxing, or "me time" to settle down. Bat caving is usually followed by whacking off and then going to sleep.
Guy 1: Why the fuck is it so dark in your room?
Guy 2: Im bat-caving, chill.
Guy 1: fucking weird-o.