When a cuckold (male spouse) is laying flat underneath his wife or spouse (usually in a 69 position) while she is getting rammed by a bull (other male)
Me and the misses just tried the under cuck the other night and the view was fantastic!
Similar to The under cuck but with a creamy ending.
I was doing the under cuck with my wife when suddenly the man spunked into my wife! Guess I ordered the under cuck suprise !