This study explores how young millennials understand and respond to newsfeed native advertising on Facebook, rooting our focus on its covert nature of the ad format. Drawing insight from two persuasion-related theories, we conducted focus group interviews and in-depth interviews with Facebook users aged 19-29. The study revealed three major themes regarding their interactions with newsfeed ads: persuasion knowledge, positive and negative experiences and avoidant coping responses. Participants showed a high level of persuasion knowledge of how Facebook newsfeed ads work and ambivalent attitudes toward newsfeed native ads. Despite some benefits, newsfeed native ads presented strong negative responses, which were often accompanied by reactance and ad avoidance. Multiple themes regarding negative experiences emerged: ad intrusiveness, ad clutter, a lack of relevance, too personal, privacy concern, goal impediment and covertness. Participants also voiced less autonomy in controlling their exposure to newsfeed ads. Theoretical and managerial implications are discussed and a model for future research is provided.