You can also get snugglers at Franklins...

I have boosted a sposie with a hemp booster (from a mcn) and that can work, but you do have to wash the booster...

Another things I do is make sure DS has a good cover over his sposie at night, like a fleece MCN cover, and that can help a bit too. I know someone who uses covers from Target for her DD and they do the trick for her.

But, I find that if he has been wiggling when I put the nappy on, I can get leaks out the top (round the waist) and I think that comes from my not getting it all lined up cause of wiggly son.