This comment has saved me embarrassment many times over the years, as I have a nice sized bust line and all crumbs are safely stored there until dinner is over!
Friend: You're always welcome here, you know that!
Magically, all eyes are diverted to my chest where quite a pile of crumbs has been stored up...
As I skillfully begin gathering up my stash, I proclaim, "food shelf!" and explain that I'll just save them up for another meal later!