Ulcgh
The only possible thing you can say when there's just no other words that would fit that specific situation.
"Yo I just stuck pizza crust in my grandma's butt"
"....Ulcgh."
"How bored are you?"
"I'm so bored, I just...Ulcgh.
"....Ulcgh."
"How bored are you?"
"I'm so bored, I just...Ulcgh.