A term used to state a claim of dominance of a female being through the act of sexual intercourse. The term refers to the metaphoric description that the male has "signed" his name on any chosen part of that particular female's body, primarily the stomach area or lower back, with his ejaculatory fluid.
"Nah man, its all good, I already signed that shit months ago at that one party."
"Dude, you better sign that shit tonight"
"Good luck with signing her up after taking her out to dinner"
The event of when the sex between two individuals reaches the point of being so explosive, that it has left obtrusive evidence of the event to the rest of the world, in some cases affecting or even harming those who happen to be innocent bystanders.
"We definitely left a fuckcrater at Robert's house party after she let me sign
"They must have been had a good one, because that fuckcrater they left took a while for housekeeping clean up."