You were pacing back and forward wondering where he was...

 *Then you saw Tweek running then he stopped next to you, panting*

"I-I'm sorry I- GAAH I'm late..."

Once you looked at him you started laughing and he looked down..

"Shit, I forgot to take off my- GAH uniform.."

Tweek was wearing his family's work uniform for his family coffee place, Tweak Bros. Coffee

"That place is b- GAHH busy, man..can you take my shift??"