Flash erection.

An erection lasting a few micro-seconds. This is invisible to anyone but the trained eye. It is an involuntary muscle reflex.

Not to be confused with a "stirring in the loins" - a more labored and deliberate feeling, involving a certain degree of participation from the subject.

when you're hungover as shit after a spending a night drunk as a skunk

Frection is an unusual surname, it is very uncommon. Its place of origin is unknown , but some believe it originated from France, however it is not proven