diapers for hyper babies

🐘🐘🐘 • 👧🏼 born 1/19/16. 👼🏼 lost 9/15/17. 👼🏼 lost 11/26/17.
So my daughter is 6 months old and is crawling like a professional. She's standing and dancing, too. Here's the problem; her diapers aren't cooperating with her activity level. They sag and fall half way down her bum. She's a slender girl, 26 inches and 16lbs, size 3 diaper. Does anyone have any diaper recommendations? We currently use luvs.