Is Bottom a State of Mind?

Recently, I was having a conversation with a friend of mine who is a staunch, life-long, dyed in the pubes top. He was looking to expand his sexual repertoire with his boyfriend, but was having trouble making the transition to versatility. He cited the usual difficulties associated with the first couple times one gets fucked — pain/discomfort, not seeing what the big deal is — but these typically go away with a with a little practice. The main problem, though, revealed itself when he shrugged and said "I guess I'm just having trouble getting into the whole bottom state of mind."

A couple weeks before this, I was at a predominantly lesbian dinner party and a conversation began about the concept of female tops and bottoms. I had never heard of this before, but all the women present seemed to know this as a reality of lesbian sex, and not just when strap-ons were involved.

So here's my question: Do the terms "top" and "bottom" dictate who does what in a brief physical act, or are they roles that one plays, in and out of bed?

By its very definition, GBS (Gay Butt Sex) requires that someone gets fucked. Dicks don't fit in peeholes and rubbing butts together isn't very satisfying, so it's just the nature of the beast that a part of one guy has to get inserted into a part of the other. The problem comes, though, when men begin to create whole identities out of what is really just a sexual position. Though few people would stand up proudly and say "I only fuck in the missionary!" it is a point of pride for many guys out there that they only top.

I too used to be really proud of never taking the passive role... until I actually tried it a couple times. And I'll be honest here folks — it's pretty awesome. Once I stopped getting caught up in concerns that I would somehow be less masculine, or that my body was somehow getting conquered, I learned that I could double the number of things I could do in bed. And variety, my friends, is the spice of life.

The double standard works both ways too. In college, a boy I'd been "knowing" for over two years was having trouble taking me, but refused to reverse the roles because he was a bottom, and bottoms don't do that. My boyfriend put it best when he said that he didn't understand how anyone could dislike topping or bottoming. People that are too narrow minded (or rectumed) to try both are severely missing out.

So for these reasons, I generally think of the roles of tops and bottoms as myths. However, hearing women talk about assuming these very same roles threw me for a loop. Does every sexual interaction inherently require that someone take a submissive role? Is it possible for any sex to take place without some sort of power dynamic being at play? I generally think it reinforces the existence of butch/femme stereotypes, for either gender, to stick so hard and fast to these roles, but it could be entirely possible that there's benefits to them that I'm completely overlooking.