He is McClappy.
https://www.buffalobills.com/video/mic-d-up-sean-mcdermott-x5834
Couple things that struck me:
1) the communication/instructions to Micah Hyde at several instances "tell everyone....". I hadn't realized how much McDermott relies upon Hyde as a leader/communicator. The Defensive Captains are Poyer, Hughes, and Edmunds. What's in a name? (~0:93 and ~3:50)
2) the specific cheering for/pumping up the O-Line at a number of points. Editing aside, kind of sheds light on what position group is most concerning to McD at the moment.
3) little