tartwater

A mixture of unsweetened cranberry juice and water. Named less for its dominant flavor characteristic than for its tendency to be consumed in quantity by a woman who is on a days-long sex binge and wants to discourage urinary tract infections (UTIs).

It is debatable whether cranberry juice can help prevent "honeymoon cystitis" or other UTIs, but drinking plenty of water and urinating after sex are commonly recommended. The tartness, as with adding lemon, makes the water somewhat more palatable.