My first post and I am using abbreviations 
What is the best method you find helps your child pass wind whilst sleeping.
Whilst it's getting better my son is occasionally grunting and straining to release the wind in his stomach. The 2 methods I use are to bicycle kick his legs and/or push on the soles of his feet forcing his knees up until his bum raises slightly.
It's becoming the best feeling in the world to hear him pop a fart out and go back to sleep. Without this he often wakes himself up trying to release gas.
Helping him pass wind is a lifesaver. I can't wait until he can do it himself.