I say, and with God's success: It is disliked to pray when one is resisting one of the two filthiest things: and the two filthiest things are urine and feces, as well as gas. Praying in this situation is disliked in both obligatory and voluntary prayers. Aisha, may God be pleased with her, reported that the Prophet, peace be upon him, said: "There is no prayer in the presence of food, nor when one is resisting the two filthiest things," in Sahih Muslim 1: 393, and Sahih Ibn Khuzaymah 2: 66. See: Al-Maraqi, p. 191, and God knows best.