(noun): The act or phenomenon of female ejaculation, i.e., the forceful expulsion of liquid from one's vagina during orgasm. (This phenomenon occurs in a minority of women.)
Vajaculation is female ejaculation aka squirting. It occurs when a female expels fluid in a flood during an orgasm. It is also known as shejaculation. According to Kinkunveiled, vajaculation is definitely not pee as it contains chemicals which are never found in normal urine and so the vajaculate is definitely a unique substance.