How do you kiss him passionatly?

Because passion is an emotional state, in order to kiss someone passionately you would have be feel passionate about that person. That being said, I think it probably boils down to subjective opinion. What you may feel is a passionate kiss may not even register on the passion-meter of another person. My advice is to ask that question of the person you intend or would like to kiss. Reducing to purely physical qualities I would venture to guess that a passionate kiss would involve holding the other person more tightly and pressing your bodies together at key points that arouses one or both parties. The pressure of one person's lips against the others would probably increase but I doubt it would get to the point of being considered a "hard" kiss. As the kiss begins I think it would begin in a more tender way with the lips parted and touching softly. The excitement and intensity would naturally escalate from that point.