Oh my gosh I had this problem with my second daughter. She is the most active girl I have ever seen. Although that was 6 years ago, I can still remember cleaning up entire rooms smeared with her dirty diapers.

One thing that I tried was overalls and one piece suits with pants. They make the diaper area a little less accessible. She did eventually stop, but she didn't potty train until she was 4 and a half.

I hope that helps a little.

i have a 19 month old boy who has found that diaper digging is the best thing in the world( in his eyes only). almost every morning and sometimes when he gets up from napping his hands, clothes and bedding are covered in poop! he only wears onesies to bed and now we've had to put long shorts on him along with the onesies to make his poop a little less accessible but he usually finds a way to get at it.
my 8 year old girl did this just 1 or 2 times and i put a diaper cover on top of the actual diaper to sleep and it seemed to work for her. too bad my son isnt that easy. any help???