Do you know this phrase? I often hear that in the US-Radio but I have no idea, what it means. Maybe a misunderstanding?
It's possible that it's "slipping around," which means to do something on the sly. For example: George suspects that his girlfriend is slipping around on him. That is, he suspects his girlfriend of seeing other men.
Are you sure you've heard right? You need an AmE speaker if so.
If not, it sounds to me like a mixture of "snooping around" (making unwelcome enquiries) and "sniping" (taking shots from a place of concealment - as in "sniper fire"). Of course, there could be an AmE sense of "sniping around" meaning something like "taking shots from a place of concealment, at random and in all directions"; but if so, it'd be news to me.
b