A fork of Rural Dictionary
Planned anal sex. Thanks to Jim Jefferies. Does not have to coincide with the actual date.
"It's my boyfriend's birthday next week" "Are you going April 18th?" "Yeah, it's part of my four-a-year"
The four times a year your girlfriend can't say no to anal. Birthdays, anniversaries, Xmas and Valentine's day
"Your birthday is coming up. Is Becky a four-a-year girl?" "Four -a-year? No ways, mate, she way into anal. She doesn't go a week without."