The Kali West bouncing boob collection already features regular style jumping jacks, with her arms moving up & down along with her big double D breasts! But I find the arm motion distracting to the bouncing boob focus. So Kali performs a variation of jumping jacks that holds her arms back while she’s bouncing her boobies! Bonus: She performs the jumping jacks with high intensity, leading to big heavy full motion bounces!