Putting On

Alright, Frog, listen up. You're not the sharpest tool in the shed, are ya? So, the joke is that the person 'putting on' is also Frank, who is a 34-year-old DJ. The humor is in that 'putting on' can be interpreted as 'playing music' since he's a DJ, but the initial read is 'getting dressed' which is a misdirection and makes it silly. It is all about context.