I am relying on what I read as well as the audio clip at the link. Chris said, "It seemed funny at the time", which indicates to me that even he may be having second thoughts about the wisdom of taking that old fossil Imus's bait. Chris made an (IMO) understandable mistake and should offer an apology one time and be done with it.
What I saw was on Fox and Friends this morning I think so I apologize if there was another incident regarding Imus and Chris that I wasn't aware of. The two guys were trying to egg on Chris into making a similar statement and Chris was trying to remain professional but ultimately said sure, I'd like to have Sarah sit on my lap. You could tell he was uncomfortable but he was after all in the company of the less professional guys on that show that like to joke around........