Erections are actually quite mystical. When it comes to vaginas and the mystery of womanhood, the idea practically sells itself. You could read the science literature, but the enchantment prevails. I mean, what exactly IS a clitoris REALLY and why does the spelling scare me so much? In contrast the word “penis” seems to wane in stature, so small and nonthreatening, and easy enough for any third-grader to read without stuttering. But while the mystic of what it means to be a woman has kept admirers clinging to the edge of their seats—basically since forever—there exists a void in the understanding of male parts as well. Erections, in particular, have been oversimplified to the same degree of assuming that just putting one into a vagina means giving a woman the best experience of her life. (This, as many men have come to discover, is not the case.) And just as it has become apparent to men that simply filling a woman’s void doesn’t make an orgasm, so too, will those who read this document, understand that a hard penis is sometimes JUST a hard penis. Nothing more. Nothing less.

Morning Wood

Morning Wood is a lot like morning coffee—the day doesn’t really start without it. And just like coffee, any morning lacking it also lacks the authentic luster of a life lived to the fullest. Every event that follows the absence of this wood is nothing but crappy theatre pining for the real thing. Rousing from slumber with a fully pitched tent is somewhat a difficult feeling to grasp if you lack the biology, though perhaps a sense of it would strive to convey an experience that embodies primal confidence, strength, and good health. This reminder of maleness and good blood flow becomes especially pertinent as the years drag on and morning pep talks involve the inevitable question of whether or not we, as men, “still got it?” What “it” is exactly I couldn’t tell you, but we need it. Truly though, it’s simpler than all of that: If our manhood is up before our brains, that’s all the green light we’ll ever need. Skip the pep talk and head straight for the next morning challenge: urinating while fully erect. Let the games begin.

Midnight Wood

Indeed, there are things that do go bump in the night: the flailing limbs of a sleepy stroll to the bathroom; a vibrating text message from that friend who waited two hours to answer you; the axe murderer gaining entry through your living room window. But other times it’s nothing more than the bed rockin’ in our dreams. Even when consciousness fades, the minds of men are keen entertainers with a full deck of memories and fantasies vivid enough to lure our anatomy into lift off. I once read that the purpose of dreaming is to keep us from waking up. If that’s the case, Midnight Wood does a great job of breaking that tradition into a million razor-sharp pieces. The sensations of pleasure brought on by an erotic dream can pack more than enough power to push consciousness to the surface. And when it happens that we do awaken, there are some options for addressing this kind of wood: rouse our partner for a multiplayer quickie; choose the solo campaign; or roll over and hope the dream picks up right where it left off.

Lazy Wood

Gay or straight—only guys could ever really appreciate this one. This works out great for our homo bros, but hetero dudes will inevitably have to tango with the confused expression of their female interests. Simply put: women are absolutely baffled by this kind of wood. Lazy Wood is a complete anomaly—an enigma even—amidst the vastness of space and time and one of Mother Nature’s final bids for immortality before global warming snuffs her out. Like a great mystery novel, the case of the unsubstantiated erection turns into the most interesting case of “Who Done It?” Nobody knows. And for these reasons, it is by far the most fun erection. I’ve been caught with Lazy Wood in nearly every romantic relationship, and the conversation always leads my girlfriends to the same question of: “But why?” The crazy part about it is that there are no specific reasons—and us guys don’t know why either. We’re not horny. We’re not thinking of anything arousing. And we haven’t stimulated ourselves manually. But yet, somehow, our anatomy executes the order to stand in attention. And though no man could ever truly explain this phenomenon, all can attest to the awkwardness evoked by the publicly Lazy Wood, which perfectly times its rousing to ensure that a maximum number of strangers watch you leave the bus or get up from your seat in a crowded room.

Pleasure Wood

Get ready to roll out the proverbial red carpet, because this is the star of the show. Basking in the lime-light of our most salient understanding of sex, the Pleasure Wood is well known for its appearance when the mood is right and it’s time to get down. In the time during and leading up to a successful sexual encounter, the Pleasure Wood embraces his upright position. First stimulated by the thoughts, images, and anticipation of its sexual desires, this erection needs little explanation and is certainly an event most familiar to both men and women. Though the Pleasure Wood is easily identified, the subtler workings of its engagement are worth noting. For example, any and all activities prior to the mixing of genitals may affect the overall appearance of Pleasure Wood, and may include (but certainly not limited to): consuming copious amounts of alcohol, having a sexual interest reveal how truly slutty they are, any and all physical harm incurred by the penis/balls combination, the foul smell of a sexual interest’s body and/or sexual parts, bad breath, horrible tattoos, multiple orgasms produced by masturbation in the preceding hours of a main sexual event, maxed out credit card statements, an encounter with a known/unknown zombie-inducing virus, any song by The Backstreet Boys and ’N Sync, the literal or perceived beginning of the Apocalypse, any and all mentions of an ex-lover, Barney, Dora The Explorer, waterbeds, Waterworld, cold water, unsightly skin legions yet to be addressed by a dermatologist, The Notebook, household chores, and the entire series of Sex and The City.