Episode 315: Poor feedback recipient and rubber duck

Do you have any advice on how to give feedback to people who don’t take critical feedback well? There’s a person who joined my team with the same job title and level as me (senior product designer/L5) more than a year ago, and since then he has shown that he not only lacks a lot of skills to be considered senior but also lacks the self-awareness to see where he falls short and how he needs to improve. There have been multiple occasions in our 1:1s where he has alluded to critical feedback he’s gotten from people on our team (including our manager) and has written it off as irrelevant or untrue, will come up with excuses for his poor performance, and will make off-hand comments about the person as a way to discount their credibility. Overall I feel like this is part of a larger display of narcissist behavior; I’ve noticed that the only time he’ll listen to suggestions is if you make it not sound critical and sandwich them in between compliments.

Up until now, I (hopefully) have avoided being on the receiving end of his negative comments, but since I’m trying to go for promotion, my manager wants me to give him more guidance and tell him directly the feedback that I’ve brought up to her. Seeing how he’s reacted in the past, I’m unsure how to just start giving him unsolicited feedback and am afraid of what he’ll think and say to others about me as someone with four less years of industry experience trying to give him advice. I’m also afraid that this will damage our working relationship as I’ve seen how despondent he becomes when things don’t go his way. I’ve told my manager these concerns and her response was that it isn’t on me if he reacts poorly to my feedback, but I feel like putting in the energy to give him feedback that he probably won’t even listen to is exhausting and isn’t worth the possibility of him becoming more adversarial towards me. What can I do? Any advice??
I recently joined a new company following the patented space law certified strategy of quit your job. I have a senior colleague who has been there maybe 8 months more than me. Whenever he has a problem, he likes to call me away from my desk and start explaining his entire problem to me. I have no knowledge of the real codebase yet and am not even an experienced programmer as I barely have 2 year of experience. I just stand there and nod and give various quips from time to time to pretend I’m listening. This can last up to 30 minutes and happens numerous times a day. If I say I’m busy he just waits 5 minutes before calling me over again. I cant get any work done because of this. How do I deal with this senior team mate that uses me as a rubber duck. Should I just buy him an actual rubber duck ?