In the old fable by Aesop, a hungry fox noticed a bunch of juicy grapes hanging from a vine. After several failed attempts to reach the grapes, the fox gave up and insisted that he didn't want them anyway because they were probably sour.
Making several attempts to get a girl you want, getting rejected by that girl, then you realizing somewhere down the line that you dont want her because shes probably sour
Prior to intercourse, a man ejaculates into a microwavable cup, then proceeds to microwaving it, thus making it sour. Then using it as lube during intercourse.
Paul, I gave this bitch a sour cream donut in her spokes because her pussy stunk.