to have one's pants & underwear around one's ankles (as if one is or has just been at the toilet)
Hann hljóp út af kamrinum með allt niður um sig. ― He ran out of the outhouse with his pants still around his ankles.
(idiomatic) to be utterly failing, to be doing a horrible job at one's tasks, for everything one is trying to do to be going comically wrong (often due to a lack of preparation)
Samtökin eru með allt niður um sig. ― The organization is doing a comically bad job these days — they are ineffective and unprepared.