An Oh my lanta moment happens when some one of the age of 20+ punches a toddler and below.
Oh my gosh Greg why did you punch that newborn this is a real Oh my lanta moment.
The split second after you've said something that you really shouldn't have said, and realise that you shouldn't have said it.
an example of the oh-shit! moment = "those jeans make your thighs look fat" ... oh shit...
When you have been drinking heavily and are having a great time, when suddenly you become extremely nauseous.
I was dancing at the frat party last night when I had an oh no moment and puked all over the pong table.