I would train it as tricks, too, to make it fun for the dog. The "go between the legs" or "circle me" type of thing. I think it would encourage handler focus too. This worked with the Collies but not so much with the terriers. Spud, at 14.5 in and 13 lbs stands sideways in front of me or besides, on her own, to block people. OE is learning this, but she is a little softer and won't stand her ground if people persist.
CA UFGRCH USCH GRCH "Spud" TT FDC CA CGC TKN
CAX UFGRCH USCH GRCH "OE" TT CA TKN FDC BCAT CGC
USCH UFCH GRCH GCH "Grytz" TT CGCU TKN FDC
CH "Doozy" FDC CGC TKN