Sometimes called "Yoner", is when one gets an erection from excessive yawning. They will often come about with no warning and are usually harder than a normal erection. They will usually happen in the morning, often during class or at work.
Guy 1: Woah dude are you getting off to our math lesson?
Guy 2: No dude I've got a massive yawn boner right
Guy 1: Oh damn I hate yoners
When someone else has yawned close by you, or you feel the intense need to yawn and are opening your mouth like a goldfish but it just aint coming... frustration squared!
Cecily: *yawn*
Girl close beside Cecily: *opens mouth* *feels intense need to yawn* Darnit Cecily, now I'm in yawn limbo because of you! *opens mouth again*