To get a girlin your Fuck Buddy list to be a hooker, just 'Do her'. After the *ahem* transaction you will be tol that she either 'ikes money' or 'is not into pleasing men'. If she 'likes money' then she will become a hooker. Just continue to 'do her' until the dial that showe her happiness with the hooker life-style is at (or near) max, and the next transaction you do select the option that means 'come work for me'. It has several different wordings but is, currently, the bottom of the three options.