If you are doing the exercises and your butt isn’t getting bigger, it may be time to switch up your exercise routine. Your muscles can get complacent when you do the same routine for a long time. When your muscles get complacent they aren’t growing.
Also, be sure that you are eating protein-heavy foods to make sure that your body has protein to develop muscles. If you aren’t eating enough protein your body has nothing to make new muscles with and is just burning fat.
Each body type is also built differently and some bodies are less curvier and more resistant to getting a bubble butt. Other bodies hold on to weight more than others and can make getting a smaller waist to get the bubble butt look harder.