The act of having sexual intercourse when an erection cannot be achieved because of excessive alcohol consumption. This can be similar to a "whiskey dick," but the flaccid penis is forced / pried into the vag. There is usually no motion involved because of the flaccidity, therefore the penis usually just sits inside and marinates. The receiver rarely receives any pleasure from the experience, and the penetrator usually gives up or passes out with it inside.
That girl got flaccid mashed last night.

I got laid last night but it was a flaccid mash and I'm pretty sure she received no pleasure from it and will never hear from her again.
by Matt F....... April 11, 2008
Get the flaccid mash mug.