Never gonna happen with Seven.

Ever.

I can't even get him to let me put a biscuit on his nose without him lifting his head and gulping it down.

It's a test of wills. I lost so I don't even try. If it's on the floor, that's another story. "NO!" will freeze him in his tracks and he'll just look miserable as he exaggerates sniffing the air and looking in its direction.