It is a condition in the temporary marriage contract to specify a dower. If the dower is not mentioned, the temporary marriage contract is invalid. If one was not aware of such a condition, sexual intercourse between them prior to becoming aware of this is not a sin and not considered as adultery.
It has been reported in some of the narrated texts that the Imams of the Ahlulbait explained the term "Faraedah" to refer to what almighty Allah has obligated in the holy Book and the term "wajib" refers to all obligations - in general - including those derived from the narrations of the prophet and the imams (peace be upon them) and those from the Holy Quran.
Religious rituals that Shias perform to mourn the tragedies of the Imams of the Ahlulbait (peace be upon them) and to present the oppressions that they suffered are recommended. However, it is obligatory to avoid what causes harm to the soul or the body. If it does not result in harm, it remains being recommended. One should avoid performing them in a place where the reputation of the Shias is damaged.