According to Todd A. Stone, author of Novelist's Boot Camp, The "Alpha Male" character "...notices physical attractiveness, feels powerful sexual urges, and responses -- if only internally -- to sexual stimulus, intended or not." However, since I write crime mysteries, I can't dwell on my character's sexual desires yet they are a part of who he is. So, how much is enough? Too much? A fellow author friend of mine said it well in one of his posts: "Anyone can write sex good. After all, it's a topic close to our hearts and one with which we're presumably well versed."
I find that it is far more exciting to read a suggestive line and "watch" the character's body language, than it is to have every detailed spelled out for me. In that respect, my imagination (and the reader's imagination) works fine. ;>)