A gentleman from another board developed this phrase a few years ago.

100% GFE on the SBS means that the lady provides all the usual GFE acronymns.

GFE + means she does something additional

GFE ++ means another activity is available.

Likewise if a lady doesn't provide certain activities she loses points, so you might see something like "90% of the SBS Scale" if for instance she didn't DFK.

But TER uses a different rating system ranging from 1 to 10 so you won't see GFE SBS mentioned here.

Have fun!