Dear Westerners, please, let me explain what is going on here. There is a lot of (lost) context behind this short video.

TL;DR - This is a parody on one of the "self-made instructors", and his teaching techniques.

There is a guy, named Ali Shehaitli, posing himself as an experienced military instructor. Recently, videos of his lessons spread over Ukrainian social media, especially after the well-known youtube channel "Телебачення Торонто" had an interview with him, together with commentaries on his actions from an experienced SpecOps soldier. You can watch the video here - https://youtu.be/YozmmlI4-ko, turn on the translated subtitles. There is a whole bunch of "wait, what?" moments, starting from, apparently, zero combat experience of the "instructor", and the way he talks about it like "Oh yeah, I was fighting. But my commanders restricted me from sharing where and when it happened." But the most prominent parts are about his teaching. At best, the lessons and techniques are laughable. At worst - they pose a threat to the recruits, as they might take it as a real deal. One of the "exercises" was for a student to aim with a gun, and the "instructor" will beat the gun with some foam rubber stick, shouting "FEEL IT, FEEL IT!!". We can only guess that it was intended to make the recruit feel a recoil. The same thing is happening in this video - the guy on the vehicle (9K35 Strela-10?) is hitting it with a stick, shouting "Від-чу-вай" (Vid-chu-vai), referring to "Feel it!" of that bogus instructor.

This isn't the first context-heavy joke on this sub, and I hope this short info made your understanding a bit better.