Tommy has cock sucker's cramp. He walks around and does his shit with his mouth half open all the time. Probably from sucking so many cocks all the time.
When you yawn and you get a painful cramp in your jaw/neck area. Sometimes it's so bad that you cannot close your mouth for a bit. It's called cocksucker's cramp because of the expression one does after yawning when he/she realizes she got a cramp it that area.
Chad : Matt yawned and his mouth stayed open for like 2 minutes.