drunken miscalculation 

Any and every time of regrettable decision or action made while under the influence of alcohol.

Yeah, I know, it was a total drunken miscalculation.

drunken miscalculation by McWebster August 19, 2010

mastubatory miscalculation 

Whe a male masturbates and he miscalculates the force of the said ejaculation and proceeds to splash his own spooge on his chin or other facial area!!!

Dude i had a mastubatory miscalculation last night and came in my own mouth!!! It sucked!!!

mastubatory miscalculation by vinny125125 September 9, 2010

anal miscalculation 

not to be confused with anal fraud

1. that's thinking youre hitting backdoor but realize you have been hitting straight back fat the moment you are about to nut. So you have to slap her in the back of the head and tell her she's trying to fraud.

dom:" I thought I was fucking this girl in the ass last night but I was just fucking her back fat so i had to slap her"

eddie:" that's an anal miscalculation"

anal miscalculation by rampage eddie June 3, 2013

Hanes Miscalculation 

(n.) the act of wearing an unflattering pair of underwear, erroneously calculating that no one would see you in your underwear for the day.

Can apply to faded, fraying, or everyday underwear brands such as Hanes or Fruit of the Loom. Is often a symptom of stag reflex.

Person 1: Lauren saw me in my workout-only boxer briefs today
Person 2: An unforgivable Hanes miscalculation.

Hanes Miscalculation by nolandc September 15, 2019