It is a british phrase. I think the most commmon usage is 'put a rocket up their arse, or 'put a rocket under them; It's similar to 'light a fire under'. It means to suggest getting somebody who has been previously sluggish in acting, to act quicker.

Yeah, definitely a common phrase in the UK, basically the sense is that if you put a (firework) rocket up someone's behind and light it, they're going to move pretty damn fast to rectify the situation before the fuse runs out.