2)Red cactus can also be a term for a whore or prostitute. It can also be used to dicribe a woman that is "An easy fuck" or someone that you can get to have some sort of sexual intercourse with you because of the possibility of her having a vaginal disease suck as, previousely mentioned, vaginitis.
Doctor: You have vaginitis.
2) Jordan: Omg, look at Cara! She's such a red cactus! I mean, look at all the guys checking her out!
Sidney: Ikr, she dresses like a total whore!