look up any word, like half chub:
 
4.
Replace any normal Adjective or adverb with Sexin to make it sound dirty, and fun. can be used in any situation.
Boy: Im so bored.
Girl: Aww, thats so freakin Sexin.
Boy: Oh, you know it baby.
by Bugeaud April 18, 2010
 
1.
When people are gettin it on!
OMG they're sexin!!!
by carly November 26, 2004
 
2.
an occasion when people indulge in group sex.
You are invited to the sex-in that takes place tonight.
by uttam maharjan September 21, 2011
 
3.
Sexin.
(1) It can be a noun!
(2) It can be a verb!
(3) It can be an adjective!
(4) It can be an adverb!

Pretty much, it can be used in any context at all. It's as openly used as fuck.
1. He's so tall...It's gotta be from the sexin.
2. And then I was all like *sexin* and ran down the street.
3. Look at that tall, sexin, awesome guy walking down the street.
4. John walked sexinly down the street, machine guns ready to go.
by LordBFG March 30, 2008