I'm a life long celibate who has never had so much as a kiss from a woman and while avoiding pornographic thoughts is easy enough to do while awake and active it becomes much harder when I'm trying to sleep and when I am asleep because everything reminds me of what I imagine a woman's touch to be like. The warmth reminds me of a warm body next to me, the blanket wrapped around me reminds me of a loving embrace, pillows remind me of a woman's body and even without all of that if I'm not actively trying to keep my mind occupied I'll start to fantasize about female companionship and that combined with being able to stay asleep for more than an hour or two at a time runs the risk of masturbating in my sleep.
I'm serious, if you want to sleep read something
Not too interesting, not too boring
But reading stuff tires you mentally--thus achieving sleep