The one day a year everyone can just acts like a total Maddog, generally a mad dogging involves getting on the piss, speaking whats on your mind, getting on the bag, going to the rippas with a large circle of friends
On Maddog day you have to be super confident and not worry about any consequences, you act without control or worry for any of your actions.
"Oi champs, this year I'm declaring April 16th as Mad Dog day, for the entire day you get to act like a total Mad Dog. God Dam"
"Only Mad Dogs are April 16th Maddog day"
Someone who spends a lot of time looking at plans/designs/blueprints.
A plan enthusiast.
Warren the plan pervert spends all day looking at plans.