That's right! On the Seventh Day Within the Octave of Christmas - even though this year it falls on a Friday, all days within the Octave of Christmas are treated as solemnities! On a solemnity, there is no penance, like abstaining from meat, so have that cheeseburger (or steak, or chicken, etc.)!
If anyone asks you why you are eating meat on a Friday, you have the opportunity to explain to them that while it is a Friday, it is also within the Octave (8 days) of Christmas - and as such is a solemnity.