Vaginal fluid protects delicate surfaces from trauma, sustains sperm and protects against infection. Vaginal fluid has a pH in the range of 4.5. There are volatile organic acids that stimulate the sense of smell. Vaginal fluid is slippery because of a high content of glycerol.
Lubricant properties enable the kind of motion that is necessary for pleasure and orgasm.
Vaginal fluid substitutes and replacements have been used for thousands of years. Olive Oil was big in ancient Greece, and Honey did it in Europe in the days of Leonardo. Thank goodness we've passed the Vaseline and petroleum product era. 4. is the first lubricant gel medically designed and tested specifically for couples .