What makes a good bottom? Well, from a bottom's perspective, the most important thing is the desire to totally satisfy the top. This means making him feel that he is in charge, doing whatever he wants, and letting him know that your only purpose is to satisfy him. If that means you have to submit to merely being a hole, that's what you do. If he wants to hear that, you tell him," I'm only a hole; use me however you want." Secondly, if he wants to feel that he is king, make sure you moan or talk to him while he is fucking you. If he doesn't like that, then keep quiet. Make sure there is variety; just doesn't lay there motionless. Contract your ass muscles, then let up and thrust back and forth, doing the work. If he wants, switch positions until you find the one which pleases him the most. If he is a romantic who likes things slow, then by all means, kiss him gently, making sure your tongue moves inside his mouth. Then, as his passion builds, go with him and increase the intensity. A good bottom gets pleasure when the top is satisfied. As the motion gets more intense and he is nearing his climax, surrender yourself completely. Don't think, just feel.
If you are a top, take charge. Let the bottom know what you like and control the session. We are bottoms because we want to surrender to the wishes of another man and not make decisions. Most of all, have fun.