I have a prayerful friend with whom I sometimes talk about prayer and spiritual things. Recently she mentioned something that really fascinated me. She said that it was hard for her to understand what a man's prayer life could be like. For her, the experience of prayer and her relationship with God was so nuptial, so grounded in her femaleness and the maleness of Jesus Christ, that it was hard for her to imagine the prayer life of a male Christian.
Certainly there is something deeply feminine about all of Christian spirituality. The Church is the bride of Christ, after all, the abiding sign and fruit of the marriage of humanity and God, of earth and heaven, accomplished in the Incarnation of the Word. Authentic Christian spirituality is always ordered to mission, and in this sense Christian spirituality is always Marian in nature: we are called to consent to the Holy Spirit's conception of the Word of God within us, which we then nurture and bear to the world. Nevertheless, we can't push the femininity of Christian spirituality and discipleship in absolute terms; the Church is also the Body of Christ, acting in persona Christi, served by priests who minister in persona Christi capitis. So perhaps it's a classic 'both/and.'
Grace builds on nature. Since our sexuality is a constitutive part of our nature, we can expect our graced and prayerful selves to be expressions of who we are as sexual beings. What is our sexuality, in spiritual terms? It is the part of the person that drives thought, affection, and body out of the self in the quest for creative and supportive bond with another. It is the drive, at the heart of our being, to live in a bond of mutual generativity. In this sense our sexuality is the means by which we come to the clearest expression of how we are as creatures made in the image and likeness of the infinitely mutual and generative Trinity.
This is the sense in which deep prayer becomes a sexual relationship with God. Not that it's a genital relationship, and not necessarily an erotic one, but a sexual relationship nonetheless because it derives from the sexuality of the person who seeks a supportive, creative, mutually generative bond with God.