A doppeldick is another seemingly identical dick. This can be in reference to your own dick or two others that you have encountered. “Doppeldick” is a riff on doppelgänger, a ghostly double or counterpart of a living person.
Wow, I totally saw your doppeldick at the sauna today.
Damn, this underwear is such a perfect fit, it would only also fit my doppeldick!
v. The act of riding a motorcycle, as a man, with another man on the passenger seat behind you: "doubledicking" or "riding doubledicker" Generally regarded as gay and inexcusable among hardcore riders.
n. A dude who rides with another dude on the back of his motorcycle.
v. Oh, here comes Adam, riding doubledicker with Steve... nasty. Couldn't they have just taken the car?
n. Dave is a real doubledicker. He'll give his buddies rides before he gives girls rides.