(n) A sleep disorder in which your friend, relative, spouse, or other acquaintance named "Jo" falls asleep without any warning. Often times this happens during text conversations. It is obvious that this happens when there is a long delay to respond to a message. Typically, you find out hours later or the next day that they just fell asleep during the conversation. This is the female form. The male form is spelled "Narjoelepsy".
"Man, I was texting my old lady Jo last night and she just stopped responding. I figured that she fell asleep again. She's got a bad case of narjolepsy"