Checking Out Her Socks
Here we see that the public humble head is discreetly checking out his customer-mistress's pink and grey bootsocks as he tongueshines her black leather boots. To be clear, he doesn't have to be all that discreet, since the Law actually requires him to study the socks of his betters - just so long as he doesn't attempt to view the customer's bare leg!
In any event, the clever customer-mistress has soon spotted that the slave is eyeing up her socks, but she lets it pass as he is continuing to do a reasonably good job of tongue-polishing her work boots, which for her is the most important thing!