O/T
Means something is really annoying. It’s like an orange that’s being a total pain in the ass.
Friend: That noise is Irritating, Disruptive, Oversized Tangerine.
Comment: That’s Irritating, Disruptive, Oversized Tangerine!
DM: Irritating, Disruptive, Oversized Tangerine. I’m done with you.