The wisdom behind drinking whilst sitting
Question

                What is the importance of drinking water in sitting position?.
Praise be to Allah.
      It is permissible to drink both sitting and standing, 
      although drinking whilst sitting is better, and it is what the Prophet 
      (blessings and peace of Allah be upon him) did most often. This has been 
      discussed in the answer to question number
      21147. 

    Ibn al-Qayyim (may Allah have mercy on him) said, explaining 
    the negative effect of drinking whilst standing and the importance of 
    drinking whilst sitting: 

    Drinking whilst standing has numerous negative effects, one 
    of which is that it does not fully quench the thirst and does not settle in 
    the stomach so that the liver can distribute the nutrients to other parts of 
    the body. Rather it comes to the stomach with speed and force, and there is 
    the fear that it will cause a chill or disturbance, and may pass quickly to 
    the lower parts of the body without moving gradually. All of that is harmful 
    to the drinker, but if he does it occasionally or in the case of need, it 
    will not harm him... End quote from Zaad al-Ma‘aad, 4/229. 

    Al-Tahhaawi (may Allah have mercy on him) said:

    It was narrated that al-Sha‘bi said: Drinking whilst standing 
    is only disliked because it is harmful. And al-Sha‘bi gave the reason for 
    which this is not allowed: because of the fear of either harm and disease 
    that results from that, and nothing else. In forbidding that, the Messenger 
    of Allah (blessings and peace of Allah be upon him) was motivated by 
    compassion for his ummah and sought to tell them to do that which is in 
    their best interests in both religious and worldly terms, as he said to 
    them, “As for me, I do not eat reclining.” That does not mean that it is 
    haraam for them to do that, rather the meaning is that there is some fear 
    for them if they eat reclining. Al-Sha‘bi mentioned the reason why the 
    Messenger of Allah (blessings and peace of Allah be upon him) disliked 
    eating reclining, and it is only because of what happens as a result, such 
    as enlargement of the belly. The same is true of what was narrated from him 
    about the prohibition on drinking whilst standing; it is only because of 
    what may result from that and he disliked it for that reason and no other. 
    End quote from Sharh Ma‘aani al-Aathaar, 4/274 

    What the believer should do is follow the guidance and Sunnah 
    of the Prophet (blessings and peace of Allah be upon him), whether he knows 
    the wisdom behind it or not; there is nothing wrong with asking about the 
    reason or looking for it so as to increase his faith or to debate, in the 
    way that is better, with those who reject this Sunnah. 

    And Allah knows best.