a chart used to catalog the frequency, duration, causation, and time of occurrence of any boner during a given period; similar to a dream diary; best formatted in an Excel spreadsheet. A boner log can be most useful in measuring one's virility or libido.
Also handy in arena of male competition.
In our double-blind, analytical study, the boner log was used to measure the virility of males age 75-80.
BRO 1: Dude, look at my boner log. I get hard every day at 3:00.
BRO 2: That's weak! Look at this. I had one for 30 minutes last Wednesday.
BRO 1: Tight, bro.