Happenis (pronounced Happiness) is the erection of a penis. Men are typically not held accountable for their actions as this condition usually leads them into relationships that otherwise they would avoid.
“What is happenis? I have a hard on… then yes - this must be love”.
To make a smile shape with one's penis on another's face.
As Justin slept after a solid rogering, Shaun placed his flaccid penis on Justin's mouth and made the shape of a smile. He took a photo of this to show Justin the HapPenis when we awoke.