My sister casually touches my crotch. The sensation is transmitted directly to my crotch, and I cum in seconds, pathetically and sadly! I cum so much that I get a stain on my pants... My sister notices and teases me, calling me a "small dick," and plays with my dick, making me cum again... But when she sees me cumming repeatedly, she gets excited and the situation changes! My cheeky sister has mellowed out and started to desire me in earnest! Is her super sensitive and premature ejaculation complex her weapon?