I have made a few.
Turning off the TV in the early hours, without switching channels from Babestation.

Currently my gentials are on fire. I have just completed making a particularly volatile curry, and needed the toilet.
I forgot to wash my hands thoroughly BEFORE going to the toilet. Everywhere feels like it has been dipped in acid. I have tried wiping with soap (an alkaline), but this is going to hurt for hours.

If only I could penetrate the missus, she could share my pain.

I disengage, I turn the page.

Shagging the barmaid from my local wasnt my smartest move TBH.

believing that schoolgirls who smoke have lower morals and will be more permissive,

and also believing that quiet swotty types were probably likely to hold the moral high ground and reject any advances.

a classic schoolboy error.

Kayla did Anfield & Old Trafford

forgetting your PE kit?

Paua oouaarancì Irà chiyeah Ishé galé ma ba oo ah

My finals German prose contained the words "his carious teeth". In the exam. room I banged my head on the desk trying to find a suitable translation into German and my brain couldn't wring out anything that wasn't feeble in the extreme.

One day a quarter of a century later it struck me out of the blue and without even trying that the correct answer was to use an encapsulated phrase along the lines of "seine durch Karies beschädigten Zähne".

That this was a schoolboy error is demonstrated by the memory of another prose we were set in the sixth form which contained a footnote to the effect that "the marble-topped table" should be rendered as "the with-a-marble-top-provided table".

I got a Third in the paper concerned :-(

Sorry, were these supposed to involve girls? There weren't any of those in my day.

============
The Ferret
============

Not exactly ''schoolboy'' but a bit of an error all the same.....
[Link]

Buy Litecoin.