Bonfuck
Bonfires can often become sexual, as everyone is hot and sweaty and thirsting to bone. This usually results in a bonfuck, when 2 or more people (Although it is considered a lame bonfire if less than 4 people are involved) have sexual intercorse with another, with penises, vaginas, and other body parts being tossed left, right, and center.
"Man did you go to Johan's bonfuck? I swear there were 15 people inside Mandy at once! It was insane, the fire was like 20 feet tall too!"