Wearing a Noodlesoother greatly improves a Sim's mood, so long as the Sim was in gold or platinum aspiration when he or she put it on. However, if a Sim in green or red aspiration puts it on, it may fail, in which case the Sim's energy will drop to zero, and the Sim will pass out.
Even if the Noodlesoother is used successfully, there's a price for using it. A Sim's motives will decay much faster while wearing a Noodlesoother. Eventually, the effects of this accelerated motive decay will outweigh the benefits of wearing the Noodlesoother. When a Sim removes a Noodlesoother, his or her mood will "crash" as the effects of this motive decay are felt.
A Noodlesoother is good for 24 hours of use. How much is left is indicated by the green meter on the front.