Ibn Majah

Benefits and Issues:
In Hadith 3423, there is mention of the Messenger of Allah (sallallahu alayhi wa sallam) himself drinking water directly from the mouth of a waterskin.
Hafiz Ibn Hajar rahimahullah has preferred to reconcile both types of hadiths in this manner:
That permissibility applies when there is an excuse.
For example, if the waterskin is hanging,
and there is no vessel available (from which water could be poured out of the waterskin and then drunk),
and it is difficult to drink with the hand—at that time, (drinking directly from the mouth of the waterskin)
is not disliked (makruh). If there is no excuse, then the hadiths that prohibit it should be acted upon. (Fath al-Bari: 10/114)

Hadith Commentary:
Drinking water by placing the mouth directly on the mouth of a water-skin (mashk) is a dangerous act; it is possible that so much water may enter the stomach unintentionally from the water-skin that it could endanger one's life. Therefore, why should a wise person do something for which he would later regret?
The same ruling applies to a decanter (surahi) as well.

Hadith Commentary:
(1)
Drinking water by placing the mouth directly on the mouth of a waterskin (mashk) is very dangerous.
It is possible that by opening the mouth in this way, so much water may enter the stomach that it could endanger one's life.
The same ruling applies to a decanter (surahi) and similar vessels.
In one hadith, it is mentioned that the Messenger of Allah (sallallahu alayhi wa sallam) went to the house of Kabsha al-Ansariyyah (radi Allahu anha).
There, a waterskin was hanging.
The Messenger of Allah (sallallahu alayhi wa sallam) stood and drank water from it by placing his mouth on it.
She, out of reverence for the blessing of his noble mouth, cut off the mouth of the waterskin and kept it.
(Sunan Ibn Majah, al-Ashribah, Hadith: 3423)
(2)
From this hadith, the permissibility of drinking from the mouth of a waterskin is understood, whereas from the ahadith of the previous chapter, its prohibition is established. How can these be reconciled? The reconciliation is that in a situation of necessity, it is permissible to drink water from the mouth of a waterskin. For example:
If the waterskin is hanging, it cannot be taken down, or a vessel is not available, and it is also impossible to drink with the palm of the hand, then in such a case, one may drink directly from the waterskin.
If there is no excuse, then the hadith of prohibition should be acted upon.
(Fath al-Bari: 10/114)