1) Making a mistake that many other people recognize as a mistake.
2) Fucking up...really bad

The utilization of the phrase varies by country.

1. (American) Failure of a device, usually in a non-repairable manner.
2. (British) Exclamation of surprised.

1. verb. To die

2. verb. To become mechanically inoperable beyond the point of repair. See also, fucked, fubar.

entymology and usage: "shit the bed" comes from the unfortunate final humiliation when an animal's (yes, including human's) bowels completely relax at the point of death, causing the contents of the colon to be expelled. To use the term as a "euphamism" for biological death is considered to be in poor taste. It is more often colorfully used in definition 2.

Something that is truly unbelievable and not good. An event or occurance that is stunning, and not positive.

In making an error, or something bad happening the expression might be used. As Shitting the bed its self could be the worst thing ever.

When something quits working or is about to stop working.

Pretty English I guess, an expression of complete suprise, or utter contempt at something that has passed. Similar to 'Christ on a bike', depending on the religious persuasions of assembled company.