I remember doing this once last year in my Chemistry college course - I was sitting down in the lecture hall, talking to some friends. I thought to myself, I wonder what everyone looks like naked, and sure enough, for the next five minutes I shut up and visualized it. I kept wondering, don't they know how hot they probably look? I'm talking about girls and guys here. When one of my friends asked me what I was doing, I said "I don't care how you manage this, I want you to go and straddle Rachael"