Something your penis made you do, or something you did with your penis that you regret.
I didn't mean to have sex with your best friend, that was a cocksident.
Or, for a kid,
Sorry mom, I didn't mean to pee all over the bathroom floor. It was a cocksident.
adj.- uneven, crooked, or otherwise gimpy
His sunglasses were cocksided on his face, because his ears were uneven.
Since the carpenter didn't use a level, the shelves ended up cocksided.
Hell, its almost sideways. Or maybe off-centre. Off-center? Who knows.
*When examining a painting.* Hm... No, no, that's cocksided.
The cringey ass nigga chef sticks his raw dick into the burger and chops the corners off like your lunch lady in elementary school and serves the burger sideways like a nigga hot dog and his dick is left in the burger.
This nigga out here really made me eat this cockside burger right side up.