Taxmas is a period after the end of the financial year when you get your tax return. It's a good way to justify spending lots of money .
May: Taxmas this year was awesome, I got myself a bunch of new rock climbing gear! What did you get?
Mike: Some hookers.
Taxmas is when an individual has gotten something that they wanted for Christmas but obtained it earlier, therefore warranting that this person may be one present short, if not presentless at all
John: I recently bought that new video game I wanted.
Jack:..oh man.. your mom is gonna taxmas on your butt. I heard she bought you it already for christmas!
John: OH NO.. I ONLY HAD ONE GIFT UNDER THE TREE!!
Wife: I bought the shoes that I had been asking for Christmas
Husband: I guess I'll have to return the ones I bought you and use the money on myself