Mr Clegg hosts a weekly 30-minute phone-in on LBC 97.3, the station where the London mayor will make a monthly appearance.
The colourful Tory will appear on Ask Boris, a 45-minute session co-hosted by the station's Nick Ferrari, who also shares the airwaves with the Deputy PM on Call Clegg.
Appearing on the show today the Liberal Democrat leader said: "I'm going to call him Slacker Johnson from now on. He's only on once a month.
"If imitation is the sincerest form of flattery I'm delighted he is trying to follow in my footsteps, but he should put the hours in.
"Every week, I want to see Slacker Johnson every week."
The jibe aimed at Mr Johnson may be seen as a riposte to some of the mayor's comments about the Liberal Democrat leader.
During the Eastleigh by-election campaign in February Mr Johnson described the Lib Dems as "wobbling jellies of indecision and vacillation, especially Clegg".