Any ideas for a toddler sleep bag pattern?

[caiesmommy]

My ds is now grown out of his sleep bags, and kicks off his blankets and with winterr coming I would like to sew him up a fleece sleep sack, but im not sure what to really do for it...if i make it closed at the bottom he'll trip when he tries to walk, if i make it open it'll ride up????

any pattern suggestions/ideas

thanks!

[LaughingHyena]

My nephews had a zip which went round one side and across the bottom, however it started at the top so you could leave the bit by his feet unzipped.