https://www.instagram.com/p/BUd7Fjsg..._web_copy_link
Looks like he has a remix deck sample set to one-shot and is just drumming it?
for me it looks like he takes a loop from the running track to deck d and fades it in with a delay?
He uses it very similar to this, minus the faders... He only use rotary 1 and 4 to control the loop size:
https://i.imgur.com/DTPVr6u.jpg
Interesting mapping there...