He probably leads up to it the same way that a gay guy might choose to discuss his male partner with his coworkers for the first time. You spool out a boring thread of conversation (nominally related to the previous topic of discussion) just so you can work an on-topic sentence where you can drop the word that's been burning your brainstem since you met these people. In hindsight your coworkers knew the only reason why you even brought up that jerk who spilled coffee on you this morning is so you can tell them that your partner gave you his vest to wear today. But if you're this dudes totes not racist slur-slinging friend you're telling your rationalist friends that your "n***a" gave you his jacket. The worst part - in the second case - is that you can totally tell when somebody is shit testing you like this, they'll put way too much emphasis on the word that has to be heard..because it's the word that has to be heard.