Christmas is a funny time. Most trends change around that time. Some terms experience a drop in frequency, others a rise. It seems that those connected with well-being and relaxation get a boost, while the problematical, the practical and the mundane drop off. It would be very nice to quantify this (if we had the data, please Google....):
For example, 'whisky' and 'vodka' go up, but 'heroin' goes down....

'Masturbation' and 'abortion' display opposing trends at Christmas:

Sometimes, of course, it is the present-potential:

Oddly, 'birthday' takes a big hit right around this time: