Whenever a girl asks me, "How do I lose this cellulite off my butt?" "How can I make my butt tighter?" "How can I make my butt more perky?" My advice usually shocks them. I NEVER recommend cardio.
My number one recommendation for an amazing ass: squats. Squats for days ladies! Bulgarian squats, jump squats, plie squats, wide squats, narrow squats, box squats, split squats, unilateral squats...whew! I'm exhausted, yes there's many more squats variety to choose from.
In efforts to make your ass smaller and tighter by doing more cardio than you should you are making it much worse, you hear me?! worse! you are losing more muscle overall that there is not enough muscle underneath your glutes therefore you look smaller in size but (no pun intended) your butt is just going to be more jiggly and loose.
And of course you should add cardio to any weight training program however it should not be your number one focus. Allow cardio to work for you by doing enough cardio to reduce body fat and weight train your butt to increase mass. If you do include cardio Stairmaster (stepmill) and high incline Treadmill walking is my go to! GOOD LUCK!
Here is a recommendation list of fitness girls that know their butt stuff!
BUTT BIBLE- by Pauline Nordin
BOOTY BIBLE- by Alicia Marie
BIKINI GLUTE WORKOUT- by Amanda Latona
by the way....yeah I'm still working on mine too ;)