The "Office boner"
When you are quietly working away in an office environment, and you start to feel a twitching in your nether regions. You want it to go away, but it just won't.
It grows and grows (and if you're lucky, grows some more...) before BOOM! You're pinned under the desk and can't move for thirty minutes.
Fingers crossed your boss doesn't call you in for a chat...
Guy B: "Why?!"
Guy A: "Had a raging Obone and couldn't make my way to the bathroom. Soiled myself at my desk."
Guy B: "awesome."