When I was in college, I knew little of the world, and made my way with women by hook or crook for much of it, collecting sexual experiences like a magpie - never counting on anything to be more than transitiory (though sometimes it was when it wasn't and vice versa). A friend, Phil, hooked it up with a girl he called he "Comic Book Dream Girl" because she (who resembled Chloe Sevigny) was this hot little raver chick with rather large breasts for her small frame, ala every comic book girl in existence. As we both lusted after her (and I seemed to have fumbled my shot) I was interested to hear of their interactions, not least of all because she had a boyfriend, making their encounter all the more illicit. What I gleaned was that they had been hanging out and he asked if he could kiss her. I then pried for more details of the seduction, and he rebuffed me: "I told you I kissed her."
As I have grown older, I have realized how right he was. You hit a certain point, and you realize it's not so much about getting the power and privledge of getting to the next base, but not fucking it up along the way to sex. Sex is only one stopping point in a relationship, and usually comes before love - or as a friend and I used to joke, sometime you sleep with a woman on the first date simply so you never have to talk to her again. To a certain extent, when you hit a certain age and setting, if you are kissing on a girl and she's receptive, the course of action is predetermined baring errors. You're going to more than likely get your groove on. In some cases, one could argue that extends even further back into the seminal meetings. Perhaps even the binary moment in meeting of "I'd fuck you/I wouldn't fuck you?" Then again work and similar get to know you situations changes that curvature, as fuckability can get into a passing grade or not passing grade with more knowledge of the subject. Though to lose fuckability is something of a misnomer with men... Losing fuckability usually means "I'd do her, but only if it meant we didn't have to talk." which can also hit a sine curve effect.