what is mean of this sentence?

What's the context?

In this clip "The Graham Norton Show" in time 7:27 amy adams said this.
https://www.youtube.com/watch?v=TuvXidK6NOM

May, hear Infra above. I guess

Whatever it was that you just did, I was vastly amused, but owing to certain implications questioning my sanity I now intend to attack you, from behind unless you're very quick

The clip that you link isn't viewable in my area so I found this one:


The quoted statement is found at around 10:21.

It means that the director liked the film shooting and wanted to shoot film from behind the actress.

The statement could be misconstrued to mean that he wanted to have intercourse with her from behind, which is why it was funny.