Longing and lust are connected. I don't think there's any argument about that. And while I don't want to offend anyone, I really believe that the longing to believe in the existence of God can easily turn into lust.
The extreme examples of spiritual lust are people that speak in tongues, chant Jesus's name, or get lost in a wave of emotion. Some will say, "These are just folks wrapped up in the Holy Ghost." Call it what you want, but it doesn't seem very much different to me than people caught up in a lustful romp.
Don't get me wrong: there's nothing necessarily wrong with a good, lusty romp. But let's call it what it is.
On the show 30 Rock, Tina Fey's character, Liz Lemon, carries the torch for "Flower Guy." When she sees him walking into a church on a Tuesday, however, she views that as a major warning sign. Why do some guys, she wonders, seem so normal, and yet have weird obsessions and dark secrets? In Flower Guy's case, he was just attending an AA meeting, which is a far more appropriate explanation for a man to be visiting a church on Tuesday in Lemon's opinion.
Explore the concept of God lust.
"God is a circle whose center is everywhere and circumference nowhere." -- Voltaire