In Iron Man 2, Rhodey tells Tony and Pepper (currently making out in middle of a discussion on the top of a building, or the open top floor of a damaged building) to "get a roof". When Tony complains that it's funny he's saying that, the buddy in question responds that "I was here first!"
In Disney's Brother Bear, Tug jokingly yells "Get a cave!" to a pair of lovebird bears. This makes sense since these are all Ice Age bears hanging out together (which they don't do in real life).
in freaky Friday harry told this to his mom and his mom's boyfriend when they're about to get a good Smooch
Adventure Time, "Dream of Love": Finn convinces Mr. Pig to tell Tree Trunks that he loves her; the feeling is a Pure clean love. This backfires on Finn when Tree Trunks and Pig keep making out in public causing lots of anxiety and nausea for everyone else. Instead of telling them to get a room, Finn tells them to make out at home, but Tree Trunks insists that it would be indecent for them to live together unmarried and they're not ready to tie the knot.