Exchanging arousing words over an instant messenger, sometimes with the intent of getting each other off. Pictures and webcams are sometimes used.
Cybering's got a bad name. It's like porn, but you get to talk to the person! (quick, guilt-free, exciting, no strings attached, and you don't have to worry about calling anybody the next day)
"Remember, kids, the only 100% effective birth control is abstinence.......and CYBERING!"
"I love to cyber and show people my naked ass on the internet!"