Nemo Rolento Combo

Hi,

So I’ve seen this combo everywhere (called it Nemo combo because I saw him did it first) but I can’t make it myself because I don’t understand if there is a trick or if I do something very wrong.

He does it here :

https://youtube.com/watch?v=-WNLJz34LRA&feature=youtu.be&t=697

It is basically whatever into EX Stinger into MD Air Raid.

I’ve tried plenty of stuff, such as every strength of MD, multiple distances for the EX Stinger, hitting only 2 of the knifes, hitting 3 knifes. I do it as fast as possible and I don’t feel like I roll back more than he does, yet I am very far from landing it, like if I didn’t knew it existed there is no way I would have thought that this could combo considering how behind I am when I do it.

Could you guys give me some tips on this one?

Thanks

Also is it character specific.? Can’t manage to land it on vega.