Diaper changes are impossible!

My 8.5 month old wiggles and flip flops all over now while i try to diaper change. I’ve tried adding toys to distract, but he just turns more. once, he just kept turning in his own poop. i’ve also tried to use a more stern tone and have even smacked his thighs to enforce gentle discipline. he just laughs and things i’m playing. 😭 he so cute. but it’s so frustrating. i’ve started to try and diaper change while he’s standing, on his belly, on his side... how do you do it?!