A Dinwoodie is similar to a woodie (or woody) and is used to describe an erection.
The main difference between a "Dinwodie" and a standard "woodie" is the origin of the state of stiffness.
A "Dinwoodie" is generally obtained as a direct result of stimulation from direct contact with lycra cycling shorts (must have chamois crotch) and friction against the saddle of a racing bicycle.
The effect is most noticable amongst cyclists who wear ridiculously coloured lycra racing outfits, cycling "spumble" helmets and mirrored sunglasses.
Some cyclists refuse to use the term due to it's ever increasing popularity amongst the general public and use the cycling fraternity "insider" definition "PB" which many members of the public thing refers to a "personal best" time when it actually means "pulsating boner"
Check that guy out on the bike, you can see his Dinwoodie !!
North Lanarkshire is full of Dinwoodies during the cycling season !!