To fall over backwards

Literally- To fall onto your back:

«The dog fell over backwards»

 

Figuratively – To make an extra effort to do something:

«She fell over backwards to organise his surprise party, and  he said he didn’t enjoy it».

 

Also, similarly, ‘To go out of your way to do something’ or ‘To go the extra mile’.

 

Video from @dogtraining68