Sex-aversary 

The anniversary of the first time you and your partner had sex.

"Oh babe happy sex-aversary"

Sex-aversary by LuvernotFiter May 20, 2010

Sexiversary 

The date on which two people first had sex.

He was invited out for a drink after work, but he knew that since it was their sexiversary and she would be expecting him to be on his game, he declined.

Sexiversary by Kate Charlton June 18, 2008

Sexiversary 

The date on which two people first had sex.

He was invited out for a drink after work, but he knew that since it was their sexiversary and she would be expecting him to be on his game, he declined.

Sexiversary by Kate Charlton June 19, 2008

sexversary 

the anniversary of the day you had sex. most easily observed once pregnancy begins; in this sense, also known as conception day.

"happy sexversary, friend with benefits!"

"wow, amy and tom! happy sexversary, and welcome to the third trimester."

sexversary by janice jim July 13, 2009

sexiversary 

The same as an anniversary, but for the first time you ever have sex or fo the first time you ever have sex with the person you are currently dating, married to, etc.
(if your first relationship is when you first had sex, then it would be a double entendre)

1. the 12th this month is my sexiversary for the first time I ever fucked someone, but the 10th of next month is my (girlfriend's/boyfriend's/spouse's) and my sexiversary for the first time we've ever had sex.
2. yesterday was my (girlfriend's/boyfriend's) and my sexiversary.

sexiversary by obamapproved September 11, 2009

Sexaversary 

The anniversary of the day one loses their virginity.

This is my three year sexaversary!

Sexaversary by reezybaby March 9, 2011