When someone is receiving a blowjob from their significant other and he/she licks down the shaft to the balls and keeps going; moving backwards between the legs to lick the taint and slide their tongue up the ass crack, in a similar fashion to that of a credit card swipe.
"Hey, how'd your hookup on Grinder go?"
"Great. We Netflixed and chilled and he gave me cow tongue."
First referanced by Dane Cook, it is the term for a vagina that is very nasty looking, or has been beat up by another man recently. It is an ultimate erection killer.
I just looked like a box of Cow Tongues down there!
"Having a tongue like a cow, smooth one way and rough the other; and hence, one who gives fair or foul language as may suit his purpose."
~Thomas Wright's 'Dictionary of Obsolete and Provincial English,' 1857
One who speaks with eloquence one moment, then swears like a sailor the next, depending on the mood or situation.
Gen George S. Patton was very cow tongued. One minute he could be giving an eloquent speech & the next minute, cuss someone out with language that would make a whore blush.