The expression "cut in on" is correct and usable in written English.
It is a phrasal verb which means to interrupt or join in a conversation or activity without being asked. For example: My friend was talking to someone but he cut in on their conversation without warning.
You and Five Leaves, that's it — " The board's chairman cut in on the microphone.
But my brain continually cut in on the dreamlike slow dance down the river.
Lewis Hamilton, Button's teammate at McLaren-Mercedes, crashed out of competition when he attempted to cut in on Kamui Kobayashi entering a corner and forced Kobayashi's front-right tire to make contact.
Doncaster took the lead straight after half time when Alford sent wing back Simon Marples racing down the right flank and he held of Stuart Whittaker to cut in on goal and slot coolly past Dickinson.
It was two after 19 minutes, Hammill tiptoeing towards Carlos Edwards, who politely allowed the winger to cut in on his strong right foot, the Barnsley man then demonstrating exactly why that was a bad idea by curling a perfect effort into the top corner.
When the hypothetical Gore nephew look-alike Mr. Boston awkwardly tried to cut in on her conversation with the tough-looking Chance, Mr. Boston seemed to have blown it, especially as he spouted nervous nerdisms like "You need Ritalin" in response to Chance's practiced baiting.
There will be no council cuts in Henley-on-Thames, one of Britain's wealthiest areas.
Place, with seams down, on one of 6 serving plates, and cut in half on diagonal.
A trumpet cuts in on the whistling, to show Trump's more aggressive and cocksure side.
The electric motor runs the car in slow and stop-start motoring and the conventional engine cuts in on the open road.
Cutting in on the angle, from the right, his shot was driven, but Mignolet stood tall, to secure a point for his side.
