My little girl does the "prawn dance" when she has wind. And it's really hard to get it out too - she is now too grown up and too cool for being over my shoulder. Tummy time helps, and a good long break (like 30 minutes) between sides at a feed. Raising her arms above her head works to get it up too, or supported standing in my lap. Anything upright, and taking her mind off it, like singing or chatting or laughing, seems to work also.