What it says on the tin. This one is a bit finicky, and can usually just end up with a bunch of naked dudes standing around a girl, which is close enough in principle, but not exactly what I was aiming for. The main tag is runatr41n, but the other tags, particularly the type of sex (vaginal sex for example) are important if you want something other than a naked crowd. 0.75 strength seems best for me, but your mileage may very.