These unnamed demons attacked Sam in his own motel room.
Upon discovering that Lucifer's True Vessel, Sam Winchester, was living in a motel room within the same city, Famine sent these two demons to attack Sam. At that moment, Sam had voluntarily chained himself to the bathroom sink to prevent himself from going mad in his hunger for demon blood.
While Dean and Castiel were out on a mission to defeat Famine and obtain his ring, Sam was approached by these two demons. They removed the cupboard blocking the doorway and were pleased to find Sam all tied up for them. Although they were ordered not to kill Sam, the female demon felt it was okay to break a few pieces.
Once the male demon had broken Sam free of his restraints, Sam attacked them both. He slit the female demon's neck and gave in to his desire to drink her blood. The female demon pleaded for her companion to get Sam off of her, but Sam was able to shove him aside, and order him to "wait for his turn". Sam proceeded to drink the blood of boths demons and then kill them.
When Sam arrived at Famine's location, he was informed that the two demons had been sent as a snack. Famine offered the other demons for consumption, but Sam was able to resist the urge and exorcised the demons instead.