Slow On The Slow On The Uptake

(I sort of help my little brother get his first job, as a busser at a restaurant I’d previously worked and where I am friends with the assistant manager. After his first shift, I ask my friend how he is doing.)

Friend: “Okay. A little slow, but he’ll get better.”

Me: *joking* “Slow as in speed, or slow on the uptake?”

Friend: “Ha ha. Slow as in speed.”

(Later, I relayed this conversation to my brother.)

Me: “So I said, ‘Slow as in speed, or slow on the uptake?’.”

Brother: “Uptake?”