How to extract and save SHSH blobs from iphone 4S?

I bought a new iphone 4s yesterday which running ios 5.1.1 this is very good but since apple is not signing this ios anymore i really don't know how to save shsh blobs from iphone itself. Because both ifaith and redsnow are not supporting fetch shsh blobs from A5 devices like iphone 4s. So does anyone have idea how to extract and copy shah blobs manually from iphone 4s through iFile or ifunbox.
It is really necessary for future restoring to ios 5.1.1

You can use tiny umbrella or something i'm not really sure? Why can't you just look it up on google videos? There's alot of videos on how to save the SHSH Blobs i've seen some