بسم الله الرحمن الرحيم
و الصلاة و السلام على أشرف المرسلين
و على اله و اصحابه أجمعين
Etiquette of Sama’
Know that tears are the expression used by the eye. We are here talking about the real eye, the eye of the heart. The physical eyes are in reality a copy of the eyes of heart and are only used for the physical word. When tears roll out, the eye of the heart is consumed by the fire of the Allah’s Desire. In such a way, that the eye is overflowed by the Tears of Love and Life.
So the physical world is directly linked to the esoteric world, we also assure that the physical world is only one of the different expressions of the deep meanings contained in the esoteric world. Consequently, if the heart is touched by the total submission and the total reliance on Allah, then the members of the body will feel exactly the same becoming as the quill writing what is contained inside the heart. And when the heart is relaxed, the skins tremble. Allah says: “Allah has sent down the best statement: a consistent Book wherein is reiteration. The skins shiver therefrom of those who fear their Lord; then their skins and their hearts relax at the remembrance of Allah . That is the guidance of Allah by which He guides whom He wills. And one whom Allah leaves astray – for him there is no guide.” 
He also says :
“And when they hear what has been revealed to the Messenger, you see their eyes overflowing with tears because of what they have recognized of the truth. They say, “Our Lord, we have believed, so register us among the witnesses.”” 
Ibn al Banna (radiAllah ‘anhu) said:
“It is not allowed to talk during Sama’/ neither to distract each other nor to smile”
Ibn Ajiba (radiAllah ‘anhu) said: “I say: for the Knowers (‘arifin), It is not allowed to talk during the Sama’, because sama’ is what accompanies wajd (swaying) and what gives access to the pure nectar. Talking takes away the Heart from The Divine Presence (Hadra) and turns it away from the Mystical Truth (Haqiqa). So it is obligatory to stop talking for he who wants to gather his heart with the Divine Presence. But for the reckless (the ignorant), it is allowed because He is close to the degree of falsehood.”
As-sulami (radiAllah ‘anhu) said: “Serenity (sakina) comes with the presence of the spirit and the heart. According attention to the poems that are sung has priority over everything else, because poems strengthen and touch the heart. As well, it is suitable for present people to keep quiet, to stay calm and listen to poems with attention during the Sama’”.
Allah ﷻ says: “And when they attended it, they said, “Listen quietly.” And when it was concluded, they went back to their people as warners.”” 
He also says: “and [all] voices will be stilled before the Most Merciful, so you will not hear except a whisper [of footsteps].” 
Distracting each other is forbidden because what is wanted is the entrance of serenity into the nafs. “Distracting each other” means to turn to something else with the body or the heart and to be kept with other things than sama’. Lastly, It is forbidden to smile because it is seen as a lack of manners and it can disturb.
As-Sulami (rahimahu Allah) added: “He who smiles, plays or is distracted should not assist to Sama’”.
It is said that Shaykh abu ‘Abdallah ibn khafif has said: “I assisted in the company of my Shaykh to a majliss in Bushran and that day people agreed to do Sama’. When Shaykh began to sway, there were among them sons of Dunia and one of them began to laugh. Shaykh took a candlestick which was close to him and he threw it against the wall (…) and he had certainly prayed thirty sunnah of subh with the wudu of ‘Isha”.