It is almost seventy year since I last played cribbage.
Mr. Dick Swiveller (is that a play on swive-ler?) having been so sick he was out of contact for many days, comes to, to find a girl he called the Marchioness playing cribbage by his bedside. She plays a jack and fails to take score.
"The Marchioness dealt, turned up a knave, and omitted to take the usual advantage; upon which Mr Swiveller called out as loud as he could--'Two for his heels!' "

I never heard that call before. We had a post about this several months ago, but it would be hard to find. I have heard it call "his nibs" and also "his nobs". What do the calcaneus bones have to do with it?

Sometimes the expression is "one for his head (your jack matches the suit of the turned up card) and two for his heels " (you turn up the Jack.)

A lovely topic! Cribbage has a vocabulary all is own, as I suppose many old games do. I know of "His Nobs" and "His Heels" (original source: local practice in Quincy, Mass) but if it's also been His Head and His Heels that would make perfect sense.

Another delightful idiocyncratic usage is declaring "Muggins!" to take points for yourself if your 0pponent (the "Pone") fails to claim them. However, my current source (http://members.tripod.com/~Germantown_Peggers/muggins.htm) says, "...First of all, you can't mug a missed cut jack"! Of course Mr Swiveller antedates, but what the Dickens did HE know?

(Afterthought: When, why, and how did Dickens get to be eponymized in that fashion? It doesn't even have an obvious target to be a euphemism for.)

Devil

http://www.bartleby.com/61/64/D0206400.html

OED traces it back to 1598 and quotes a 1656 source as saying it was a corruption of Devilkins.