due to extreme tiredness one becomes giddy with uncontrollable laughter, also described as naturally high
Jenkins:"Hey Bob! guess what?"
Jenkins:"Dude you're so slaphappy"
1) When someone slaps the hell out of a hooker.
2) Uncontrollable masturbation.
3) Easy to anger.
1) He got slaphappy with Amber.
2) Dude, you gotta stop being so slaphappy. I need to use the bathroom.
3) Don't piss of John. He's slaphappy today.