What it means
Cuffing season is the cold stretch from autumn into winter when people suddenly want to be coupled up, swapping summer freedom for someone to hibernate, share blankets and dodge the cold with. Come spring, a lot of these pairings quietly melt away again.
Usage examples
"He never texts in July but come October, cuffing season, suddenly he is all in."
"They got together in cuffing season and broke up the week the sun came out."
"Soon as the clocks change, he's out here looking for a plus-one like cuffing season punched in."
"They were pure cuffing season vibes, matching hoodies in November and ghosting each other by April."
Where it comes from
It comes from cuff, meaning handcuff. The joke is that once the weather turns grim, people start wanting to get metaphorically cuffed to someone for warmth, company, and winter cosiness. The phrase took off online and in pop culture to label that autumn-to-winter rush into short-term couple mode.