The camera angle in pornography that shows a full view of the penetrator's anus, scrotum and perineum. Can also be used to describe the scene viewed by a non-participating partner in a threesome, or by walking in from an unfortunate angle on a couple in mid-coitus.
Right after I finished, the porno went full grundlevision. I think I'm gay now.
I went to get more champagne and when I came back, they were going at it. Took me almost a week to forget the grundlevision.