A group expedition on bikes up to the Cime de la Bonette in Southern France.
Note: Not involving sex in any shape or form, I want to make that quite clear.
Big Al: Guys are you going to come on the Bonathon at the end of the month?
Tiny Tim: You bet your ass!
Fred: I'm in.
Kim: I'll be there
Profession-Al: Try and stop me.
An event in which boning takes place on a very large scale, this includes homo or heterosexual relations, but usually homo.
Thom, Jarrett, and I all took part in a huge bonathon last night.