Sheikh Ahmad al-Rashîd
Combining between two prayers (either Zuhr with `Asr or Maghrib with `Ishâ’) is a concession granted to us by Allah as a mercy to us to make matters easy for us. It is authentically established that the Prophet (peace be upon him) combined between two prayers on several occasions.
This provides some flexibility for the worshippers.
However, combining between two prayers is not permissible at all times. Normally, prayers should be performed at their properly appointed times. The permission for combining between two prayers at one time exists only for certain extenuating circumstances, such as travel, sickness, and the like.
It should be noted that there are some general conditions for combining between two prayers as determined by the people of knowledge, and these conditions must be fulfilled.
Combining between two prayers for a valid reason exists as a concession to ease things for the worshippers, and as such, it should not itself become a source of difficulty.
For example, the traveler may combine and shorten prayers while he is traveling. If he combines between Zuhr and `Asr in his travel, he is not required to continue his travel immediately after performing the combined prayers. He may sit and rest afterwards for a while and then resume his travel.
Likewise, a traveler who knows he will arrive at his destination at the time of the `Asr prayer may still combine between Zuhr and `Asr at the time of Zuhr, He will not be requested to offer the `Asr prayer again upon arrival.
Accordingly, if the European Fatwa Council has ruled it to be permissible for people under such circumstances to combine between the Maghrib and `Ishâ’ prayers, then you may sit for a while after completing the combined prayers at Maghrib time, in the manner that you have described in your question. This is because if you had been obliged to go to sleep immediately after Maghrib, this would be itself a source of difficulty, and combining between two prayers is permitted for the express purpose of alleviating difficulty.
And Allah knows best.
Source: Islam Today