so i've seen a bunch of stuff about how to open a set and do the simple stuff like #-closing. Then on the other end of spectrum, I've read a bunch of stuff about how to f-close after she is at your place. This leaves a bit of a gap. How does one go for the middle ground (specifically k-close)? I'd love to hear some theory or get links to articles about how to do it (in all the frs ive read it just happens).