The researchers selected six different "Wholesale body lubricant", four of which are water-based lubricant, two kinds of silicon lubricant, ladies can attend one of the free trial. After five weeks, and they need to "Wholesale body lubricant" record their daily life in the "coefficient of friction" (where "coefficient of friction" refers to the process in sex if there is discomfort in the specified web page, such as the penis insertion pain, itching, etc.) and Flirt index (degree of sexual satisfaction and sexual pleasure). In five weeks, the first one week before they can talk, try to use the second and third weeks of "Wholesale body lubricant" in sexual activity, the last two weeks are not. The so-called sexual intercourse can be vaginal, DIY or anal sex.