Based on the face of Twitch streamer @Oddler - when on September 19th, 2012, he passed out during his 72 hour Resident Evil marathon attempt (at 65 hours, 43 minutes in). He went from around 900 viewers to 13k during his 30 minute long nap. The emote is used to signify sleeping, or otherwise boring stream content.
Original picture (screencap from Oddler's stream): https://i.imgur.com/za3gYwz.png
Twitch - Global supinic.com
