"Bonus" sexually means gettin some head. (usually the male say's this) Ex. "Yeah I smashed it, plus got the bonus"
When meeting the opposite sex and ya'll attracted to each other, eventually sex willhappen but normally not oral sex. So when you get some head it's considered or called a " Bonus"
A questionable Canadiangame where one person would yell bonus and place both hands flat together and shove the finger tips into another’s unsuspecting anus.
Funny as shit if its not you on the recieving or giving end.
"holy shit richie did you see how deep john's bonus can go!"
or
"man john is such a fag all he ever does is bonus me"