I have a friend who desires to be slain in the spirit. He somewhat envies those who experience this phenomena. I don't know how to address this desire he has. It's more than a conversion experience, rather, it's something that overwhelms one. It is the very presence of God in one's life, to such an extent that it overwhelms one, to the point where you can do nothing except God's cleansing of your spirit and soul. I speak with first-hand experience of this.
I have somewhat of a disdain for those desiring physical manifestations of the Holy Spirit, yet, I desire it at the same time. A conundrum, if you will. I believe that it is a personal experience that can only be accepted...personally. When it happened to me in 1988 I was awe-stricken. It changed my life forever. But it was me...in God's time and at His place for me. I cannot command it nor entreat it. It is personal.
I see it, in reflection, as an event that God had planned for me. It was personal. If God so deems to reveal Himself to another the same way...I'm all for it. But if He withholds and decides not to reveal Himself to others...may His will be done. My heart hurts for my friend, as he deeply seeks a closer relationship with God. Perhaps, in time, God will wreak his heart, and overwhelm his existence, that he feels slain. In the Lord's timing...only.