Initials of "Disregard that, I suck cocks", a phrase from 4chan
used on the internet when
someone wants to take back what he said, e.g. when
someone finds out something that
contradicts what they previously
Because the initials don't have the swearing explicitly written, this form can be considered more polite
than the full phrase.
Alice: I think
this one joke, I'm almost sure about that...
*she finds out Charlie told
it, not Bob*
Alice: DTISC, it was Charlie.