Hey guys, it's been a while since i've posted anything, and I was wondering if anyone could help with this concept. My friend mentioned it in passing, but I didn't think anything of it. Then the next day he called me and told me he had hooked up with two girls that night. It would be most appreciated if anyone could elaborate on what this concept is, give examples, and advice on how to implement this concept. (My friend is very bad at explaining it.)