I can't recall ever walking IN with wood, but will quickly get one if all the right factors are in play. Things like, you looking hot, smelling good with that 'smell good' shit y'all be wearing that smells all girly and shit, a warm greeting that involves a hassle free process of getting to your incall, all the way up to that first embracing hug, and other subtleties here and there.
All of these just add a few pumps of blood to the groin area. A tingly kiss could do it. I remember going into one session, where the woman was standing at the top of a staircase in a short black skirt, curvy hips and thighs everywhere. I started getting IRON right there. In two seconds, I had that painful hard-on. I was literally THAT FUCKING HARD. At that moment, I've never wanted some pussy so bad before in my life!!!
At the same time, some ladies are just lost on the art of 'wood making'. Many times, they do the opposite of all the above. Not looking hot. Acting distant. Not fresh. Not into it. Had to go through a gauntlet to get to her (terrible directions, 'vultures' i.e. pimps, neighborhood creeps, weirdos, etc near the incall), crappy incall, touching my dick with ice cold hands, etc. Sometimes, ladies, it IS you.