No, it's not a joke. Researchers at the University of Bari, Italy, studied how MDMA (ecstasy) and loud music impact the sexual activity of rats. They report their results in the scientific journal European Reiew for Medical and Pharmacological Sciences. According to their experiments, MDMA impaired the rats' sexual behavior while loud music seemed to increase the number of rats getting it on. From the paper abstract:
However, combined treatment of MDMA and music stimulation did not fully restore normal sexual behavior as the animals reaching ejaculation still showed a marked reduction of copulatory efficiency. These findings demonstrate that the systemic administration of a single low dose of MDMA, alone or in combination with loud music, which is commonly present in certain environments such as rave parties, notably impairs copulatory activity of male rats.