Can only be used in the immediate aftermath of or during someone sleeping with your wife.
Upsetting man: Oh, sleeping with your wife.
See also: GARSP, Gasp, :o
* Trev-MUN points at Beige.
<inmastein> Beige is an anime girl?! D:
Generally, because A: is reserved for a 3 1/2 inch floppy drive, B: for the obsolete 5 1/4 floppy drive (the letter is skipped if the drive does not exist), and C: for the first hard drive, D: is most often a second hard drive or a first CD-ROM drive.
Letters thereafter, such as E:, F:, G:, etc. can be filled by CD-ROM drives, burners, external hard drives, USB drives, and the like as necessary. While not required to be in alphabetical order, it is this way by default.