His penis is his bodily root. The flower of his heart opens widest when his root is planted deep in your body. We are not discussing the mediocre lover. For him, the penis is simply an appendage of pleasure, a sensitive finger with which to enjoy your juicy friction. But as a man continues growing in his sexual capacity, his genitals can help ground his consciousness in his body and yours.
Most men tend toward being heady and disembodied.
Your man probably thinks, plans, and mulls things over in his head all day. Then, for a few moments of sex with you at night, his energy goes to his genitals, from whence it spews. Your sexual ministrations draw him briefly into his body, where he feels a lot more present with you than when he is in his head. When a man first starts growing sexually, he will probably be rather heady. He exerts effort from his head.